Read the following passage and questions, then choose the right answer from options, the answer should be one of A, B, C, D.

<passage>:
Obstetrics for beginners It's my first go at delivering a baby by caesarean section – and the foetal head is impacted, jammed in its mother's pelvis. To be honest I'm struggling. Incisions have been made in the lower part of the mother's abdomen and womb. I've pushed my gloved hand inside and managed to slide my fingers between the baby's head and the surrounding uterine tissue. But it's difficult. The baby is tightly wedged in. I've had to push hard to get my hand to the far side of its head, and even though I'm now cupping and grasping it in the approved manner, I can't seem to pull it out. Dare I grip its head more firmly? Dare I pull harder? The baby's mother – she's called Debra – remains impassive throughout these agonised fumblings. Her face reveals nothing of what she may be feeling. But then Debra has no feelings. Indeed she has no face…So you can stop worrying. Debra – Desperate Debra to use her full trade name – is a simulator designed to help doctors practise their skill at dealing with impacted foetuses: babies that get stuck trying to exit the womb by the normal route. She comprises the lower two thirds (ie from the mid-chest region downwards) of a life-sized but limbless female torso made of flesh-coloured silicone rubber. She comes with a vulva, a pre-cut incision in her abdomen and, most importantly, a uterus containing a foetal head that should, in the normal way of things, be free to emerge between her legs. But this fetus is going nowhere until an obstetrician – or in this case me – can successfully grasp and pull it out. The clever and sophisticated simulator I'm playing with started life as a lash-up in an obstetrician's home workshop: a Heath Robinson-style contraption barely recognisable as a model of the human body. But it wasn't at that stage intended as a simulator for training medical staff. Its sole purpose was to test the effectiveness of a novel device called a Tydeman tube. Paradoxically, although the testing equipment, Debra, is now commercially available, the device it was intended to test has yet to reach the market. but with a good outcome. Although the Tydeman tube is still in gestation, Desperate Debra herself is now thriving. To understand the desperation of Debra and how the Tydeman tube might help to relieve it requires a brief foray into basic obstetric knowhow.  Evolution has endowed us with heads proportionally so large that even when labour runs according to plan, the delivery process involves a bit of a squeeze. For the baby's head to get stuck on the way out may not be usual, but it's by no means a rarity. The standard response is to perform a caesarean section. Every year some 160,000 babies are born in the UK this way, with almost two thirds of them classified as emergencies. One audit has suggested that roughly 8,000 babies get stuck and have to be delivered by caesarean at a stage when their mothers are fully dilated. "Some of the babies will be so close to coming out by the normal route," says Tydeman, "that it's then difficult to get them back up and remove them through the hole in the woman's tummy." Which women are most at risk of this setback seems to be largely unpredictable. "We just observe that it happens… It's been discussed in the medical literature since the 1940s, but until 10 years ago, and throughout my training and most of my life as a consultant, it wasn't really talked about." which suggests requests for push-ups during unplanned caesareans are far from uncommon. The Tydeman tube is a gadget intended to make this manoeuvre safer and more effective. Creativity and innovation have many unlikely sources. What seems to have inspired Tydeman to develop his device was the characteristic sound of a Wellington boot being pulled free of wet, muddy ground: a slurpy, sucking, gurgling noise. When an impacted foetal head is pulled free of the uterus it's often accompanied by a similar sucking noise, the result of air rushing in between the obstetrician's fingers to fill the space vacated. "What occurred to me years ago was that if the air can't get in, why not put a tube up into the vagina so that it can get in from below the baby's head." From time to time, if he felt he felt the baby might stick, Tydeman would slip a length of sterile silicone tubing through the woman's vagina and up into the womb next to the baby's head. Allowing air in by this route would release any suction forces tending to hold it where it was. Tydeman didn't do much with the idea until 10 years ago when one trainee, who was experiencing real difficulty getting heads out, prompted him to think again about the problem. Around the same time, he met professor of obstetrics Andrew Shennan and consultant midwife Annette Briley, both of the Women's Health Academic Centre at St Thomas's hospital. Between them they came up with a device – the Tydeman tube – to make pushing on the foetus more controlled while simultaneously releasing any vacuum that might be holding it in place. The instrument is made up of a rigid plastic tube opening into a softer silicone cup. Pressure to the foetal head is applied using four pads projecting forward from the cup's interior. Holding the device by the tube, the user places the cup against the part of the head exposed through the dilated cervix, and presses. This pushes the baby back up into the uterus while releasing any suction pressure that may have been holding it, so allowing the obstetrician to extract it more easily. Because pressure is distributed equally between the four pads with a greater combined surface area than that of a user's fingertips, the risk of inadvertent damage is minimised. The team found some money to employ a product designer who used computer-aided design technology and 3D printing to make a prototype. "We were at the point of getting one made in silicone," says Tydeman, "when we realised that before we started experimenting on women we really ought to test it on a simulator." No such simulator existed – so he decided to make one himself. That Tydeman was able to do this comes as no great surprise once you've glanced at his website. His career may be rooted in medicine but his interests encompass sculpture, furniture making and much else. He works in wood, glass, metals and plastic. "I've got a big workshop with a lathe and a forge," he says. "I make stuff. I always have, ever since I was a child. My dad was a woodwork teacher, my mum was very creative with fabric."

<question>:
What does the Tydeman tube do?

<options>:
A The Tydeman tube is placed in the uterus near the baby's head. The tube opens into a soft silicone cup, which is placed on the part of the head that is exposed through the cervix. Pushing air in through the tube releases suction forces that may be holding the baby in place.
B The Tydeman tube is placed in the uterus near the baby's head. The doctor can inflate or deflate the tube as necessary to help ease the baby out of the birth canal.
C The Tydeman tube is placed in the uterus near the baby's head. The tube opens into a soft silicone cup, which is placed on the part of the head that is exposed through the cervix. Pulling air out through the tube releases suction forces that may be holding the baby in place.
D The Tydeman tube is placed in the uterus near the baby's head. Pushing air in to inflate the tube keeps the umbilical cord from closing around the baby's neck.

<answer>:

A