An outlet pipe can empty 3/4 of a cistern in 12 minutes. In 4 minutes, what part of the cistern will be emptied?	Choices.
A) 1 / 2	B) 1 / 3	C) 1 / 4	D) 1 / 5	E) 1 / 6

Rationale: "4 / 12 * 3 / 4 = 1 / 4 the answer is c ."
Answer: C