Estimate the number of cells that belong to each phase of the cell cycle

There are two ways to do this.  You could actually learn the phases and count each one.  Since you're posting here, it's a safe bet you have no intention of actually learning the material.  The second is to estimate based on the total number of cells.  At any given time, you will have approximately the following percentages for each phase of the cell cycle:

Interphase - 96%

Prophase - 2.5%

Metaphase - .5%

Anaphase - .5%

Telophase - .5%

In the picture, there are about 120 cells.  Now you have to do a little 5th grade math to calculate the approximate mumbers of each phase.  So, for Interphase, we multiply 120 x .96 = 115.  For Prophase we multiply 120 x .025 = 3.  For Metaphase, Anaphase, and Telophase, we multiply 120 x .005 = .6, which rounds up to 1 each.  Now, as I specified, these numbers are approximate.  Looking at the picture, I count three that are in Metaphase, two that are in Anaphase, and at least three in Telophase. And there are more than three in Prophase.  The best way to figure this out is to print the picture and, using a guide from the internet, count the cells in each phase, marking them off as you count them so that you don't recount them.  Good Luck!

the answer to your question is:

c. complementary base-pairing