Answer (D)
"None of my friends are perfect."
Its negation is atleast one of my friends is perfect read the negation again and think
atleast one of my friends is perfect
∃x(F(x)∧P(x))
we use ∧ because I want to test my friends and true value should come from them not from outside people
if we used implication we will get true value for a person who is not even my friend and ∃x to be true only needs one true value.
now negate ∃x(F(x)∧P(x))
=> ¬∃x(F(x)∧P(x))