The correct option is D Both Assertion and Reason are incorrect.
In p-nitrophenol, −NO2 group has −I effect, as a result of which electron density decreases on the benzene ring, hence reactivity towards electrophilic substitution decreases. Methoxy group show both +R (due to lone pair of electrons on O) and −I effect (due to greater electronegativity of O).
−OCH3 at meta-position shows only −I effect but lesser than −I effect of −NO2 group.