During active labour cervical dilatation per hour in primi is: .: (A) 1.2 cms, (B) 1.5 cms, (C) 1.7 cms, (D) 2 cms
Answer is A. Labour is said to active when:

Cervix is dilated to at least 3 – 4 cm.
Regular uterine contractions are present.
Rate of dilatation is at least 1.2 cm/hr for nulliparous and 1.5 cm/hr for parous women.