This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
Floor of posterior triangle of neck is formed by 
Select and explain. 
A. Semispinalis capitis, elevator scapulae, scalenus anterior, scalenus medius, B. Levator scapulae, splenius capitis, scalenus medius, scalenus anterior, C. Semispinalis capitis, scalenus anterior, splenius capitis, sternocleidomastoid, D. Levator scapulae, scalenus posterior, semispinalis capitis,scalenus medius
D: Levator scapulae, scalenus posterior, semispinalis capitis,scalenus medius
Answer: D: Levator scapulae, scalenus posterior, semispinalis capitis,scalenus medius 
Explanation: Muscles forming floor of posterior triangle of neck :

 Semispinalis capitis.
 Splenius capitis.
 Levator scapulae.
 Scalenus posterior.
 Scalenus medius.