Explanation:

- Option 1: In cases of non-bailable offences

- Section 438 of the CrPC can be invoked in cases of non-bailable offences.

- This section provides for anticipatory bail, which allows a person to seek bail in anticipation of being arrested for a non-bailable offence.

- Option 2: In cases of bailable offences

- In bailable offences, bail is a matter of right.

- Therefore, Section 438 is typically not required for bailable offences.

- Option 3: Both (a) & (b)

- Section 438 primarily caters to non-bailable offences, not both types.

- Option 4: Neither (a) nor (b)

- This would be incorrect as Section 438 does apply to non-bailable offences.

Option 1: In cases of non-bailable offences