Step 1: Recall plant classification.
Muskmelon (Cucumis melo) belongs to the family Cucurbitaceae, which includes cucurbits like cucumber, pumpkin, watermelon, and gourds.
Step 2: Eliminate wrong options.
(B) Brassicaceae – includes mustard, cabbage, cauliflower.
(C) Amaryllidaceae – includes onion, garlic.
(D) Malvaceae – includes cotton, hibiscus, okra.
Step 3: Conclusion.
Therefore, muskmelon belongs to the family Cucurbitaceae.