PLease answer a$-$d$.$ thank you! Calculate the future value of $$7,000$ in

a$.4$ years at an interest rate of $7\%$ per year.

b$.8$ years at an interest rate of $7\%$ per year.

c$.4$ years at an interest rate of $14\%$ per year.

$d.$ Why is the amount of interest earned in part a less than half the amount of interest earned in part $b?$

a$.4$ years at an interest rate of $7\%$ per year.

The future value of $$7,000$ in $4$ years at an interest rate of $7\%$ per year is $$,.($Round to the nearest dollar.$)$