In what phase of mitosis do the centrioles separate?

Prophase

Explanation:

During prophase, chromatin condenses into chromosomes, and the nuclear envelope, or membrane, breaks down. In animal cells, the centrioles near the nucleus begin to separate and move to opposite poles (sides) of the cell.

Prophase

It's the longest phase of mitosis. when the nucleus divides, the two chromatids that make up each chromosome separate from each other and move to opposite poles of the cell