Which one of the following belongs to the family Muscidae ?

The correct option is House fly.

To understand why, let us look at the taxonomic classification of the house fly (Musca domestica):

Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera (true flies)
Family: Muscidae
Genus: Musca
Species: M. domestica

The family Muscidae commonly includes house flies, stable flies, and related insects, which are characterized by having a single pair of wings (Diptera) and specialized mouthparts for sponging or biting.

Let us briefly check the other options to see why they do not belong to the family Muscidae:

1. Fire fly: Belongs to the family Lampyridae (Order: Coleoptera).
2. Grasshopper: Belongs to the family Acrididae (Order: Orthoptera).
3. Cockroach: Belongs to families such as Blattidae or Ectobiidae (Order: Blattodea).

Therefore, the house fly is the correct organism belonging to the family Muscidae.