If AC is a diameter, which of the following must be a semicircle?
ABC
ACB
TCR

Answer:
A. ABC.
Step-by-step explanation:
We have been given an image of a circle. We are asked to choose the arc, which must be a semicircle of our given circle.
Upon looking at our given diagram, we can see that AC divides our given circle into two semicircles ABC and ATC.
From our given choices, we can see that option A is the correct choice.