"regrouping 1 tenth into 10 hundredths" is taking one of those green tenth sticks and dividing it into 10 hundredth squares. That means that you have 2 wholes, 2 tenths (remaining green sticks), and 10 hundredths (because the only hundredths you have are the ones you got from that tenth you regrouped).
After crossing them out, you have 2 wholes, 0 tenths (because you only had 2 before), and 4 hundredths (because you crossed out 6 of the 10, 10-6=4).
Binomial means that it will have two terms, so by process of elemination, we are only left with C and D. Degree would be the power, and D is the only one that has a power of 2.
