Which species have one or more atoms that Violate the octet rule?

(P) NO  (Q) ${\mathrm{SF}}_2$ 

(R) ${{\mathrm{PF}}_4}^{+}$

An atom must create a link, under the rule, in order to have eight electrons in its valence shell.
The molecules with an incomplete octet and those with an enlarged octet are the exceptions to this rule.

Hence, Option A is correct.