In Arabic morphology (علم الصرف), the morphological pattern (وزن) of a word is determined by mapping its root letters onto the template letters ف-ع-ل.
The word "منزل" (manzil, meaning "house" or "dwelling") comes from the root ن-ز-ل (n-z-l, relating to descending or staying). Mapping the letters:
م - extra prefix letter (زائدة)
ن = ف (first root letter)
ز = ع (second root letter)
ل = ل (third root letter)
The pattern is therefore مَفْعِل (maf'il), which is the standard pattern for nouns of place (اسم المكان) and nouns of time (اسم الزمان) derived from trilateral verbs whose imperfect has a kasra on the middle radical (نَزَلَ / يَنْزِلُ). The option مفعل (which appears to contain a typographical error in the question) corresponds to this pattern and is the correct answer. The other options - مفعلة has an extra تاء مربوطة, فعال lacks the م prefix, and مفعول is the passive participle pattern - do not match.
