Answer
$3125$
Work Step by Step
We are selecting five elements, each of which can be any of the five elements $a$, $b$, $c$, $d$, $e$, with repetition allowed. There are $5$ choices for the first element, $5$ choices for the second element, and so on. By the product rule on page 386, the total number of ways to select five elements is $5*5*5*5*5=5^5=3125$.