$V = I\,R$ is one fact in three outfits. Solved for the current: $I = \dfrac{V}{R}$. Solved for the resistance: $R = \dfrac{V}{I}$. Same law, asked from a different side — the exam picks the outfit, and your job is to pick the matching rearrangement BEFORE any number moves.

Here is a friendly check that never lies in one direction: run the units through. Ohms times amperes makes volts, so $V = I\,R$ passes. Volts over ohms makes amperes, so $I = \dfrac{V}{R}$ passes. If the units refuse to come out right, the rearrangement is wrong — no appeal. (Units that DO work out never prove you right, though — the check is a one-way street.)