its bc this are the only 2 muscles on the orbital floor google orbital floor muscles in google images https://www.google.com/search?q=orbital+muscles&tbm=isch#imgrc=NNOONaLRFuEP1M:

Inferior oblique = helps you look up & in.

Also, they said floor of the orbit, so it makes sense that the inferior muscles would damaged.

Option A is the only option where both muscles are part of the orbital floor. Also, the last sentence in the question stem is a total modifyer of what one would expect the question to be asking. It is not asking for you to assume that these muscles have been severed, paralyzed, or rendered flacid. It is asking you to assume that they have become "entrapped" if the muscle is entrapped, then it cannot allow the eye to move into whatever position it would be in when the muscle is at its lengthened position. So in this case, It is the inferior rectus being entrapped in a functionally shortened position that is preventing upward gaze.

Orbital floor fracture:

1- Infraorbital nerve injury: Numbness and paresthesia of the upper cheek, upper lip, upper gingiva.

2- Entrapment of the inferior rectus muscle: Impaired upward gaze

3- Enophtalmosis

4- Clousing of maxillary sinus: Teardrop sign

The obliques do the opposite action of their name. Inferior oblique moves the eye UP and OUT (extortion, elevation, ABduction). Since the question says that there is a fracture involving the orbital floor, that automatically rules out D (medial rectus and inferior oblique), leaving the only logical answer to be the inferior rectus and inferior oblique. https://www.youtube.com/watch?v=lWKkHWWDIEI