PLEASE HELP!! Which of the following functions represents f(n), the number of small squares in figure n?

A. f(n) = (n + 1)^2 – 1

B. f(n) = 2n^2 + 1

C. f(n) = n^2 – 1

D. f(n) = (n + 1)^2 + 1

Suppose that sahil knows that 45 people with ages of 18 to 29 voted. without using a calculator, he quickly says then 135 people with ages of 30to 49 voted. is he correct? how might sohil have come up with his answer so quickly?