Question

A tubal ligation is a permanent sterilization procedure in which a woman's fallopian tubes are blocked or severed. Which of the following explains how this process can be used to prevent pregnancies? It prevents sperm from reaching the egg and fertilizing it. It prevents the maturation of the follicle and the release of an egg. It prevents a zygote from being implanted into the uterine wall. It prevents the thickening of the walls of the uterus.

Answer 1

It is the first one, prevents sperm from reaching the egg and fertilizing it :) (made fairly obvious in the question where it states they are blocked/severed.) 

Answer 2

It is the first answer because it blocks the sperm from getting to the eggs.