Answer
Valid by universal modus ponens.
Work Step by Step
Universal modus ponens: $\forall x, $ if $P(x)$ then $Q(x)$.
$P(a)$ for a particular $a$.
$\therefore Q(a)$.
In this case P(x) is: If a person is a freshman.
QIx) is: that person must take writing.
a is Caroline.
