Domain: Set of natural numbers.
Let,
P(n): n is prime
A(n): n is antisocial
Then,
If n is prime, then n in antisocial $ \equiv \forall_n(P(n) \to A(n))$
Now considering n = 10, and we know $P(10) \equiv False$
$P(10) \to A(10)$ $ \because $ Universal Instanstiation.
$\neg{A(10)} \to \neg{P(10)}$ $\because A \to B \equiv \neg{B} \to \neg{A}$
$\neg{P(10)}$
$--------$
Cannot infer anything
Now considering n = 7, and we know $P(7) \equiv True$
$P(7) \to A(7)$ $ \because $ Universal Instanstiation.
P(7)
$--------$
$\therefore A(7)$
$\therefore$ Correct option is C. 7 is antisocial