Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): In expensive scientific instruments, silica gel is kept in watch-glasses or in semipermeable membrane bags.
Reason (R): Silica gel adsorbs moisture from air via adsorption, thus protects the instrument from water corrosion (rusting) and / or prevents malfunctioning.
In the light of the above statements, choose the correct answer from the options given below:

We need to evaluate the Assertion-Reason pair about silica gel in scientific instruments.

Assertion (A): In expensive scientific instruments, silica gel is kept in watch-glasses or in semipermeable membrane bags.

This is TRUE. Silica gel sachets or containers are commonly placed inside instrument cases and packaging.

Reason (R): Silica gel adsorbs moisture from air via adsorption, thus protects the instrument from water corrosion (rusting) and/or prevents malfunctioning.

This is TRUE. Silica gel is a desiccant that works by adsorbing water molecules on its surface, keeping the environment dry.

Relationship: R correctly explains A — silica gel is kept in instruments precisely because it adsorbs moisture and prevents damage.

The correct answer is Option 3: Both (A) and (R) are true and (R) is the correct explanation of (A).