Explanation:

- Option 1: Inadequate soil conservation measures

- Soil conservation measures are vital for preventing land degradation.

- Lack of these measures can result in erosion and loss of fertile topsoil.

- Option 2: Overgrazing

- Overgrazing by livestock can strip vegetation cover.

- This makes soil vulnerable to erosion and degradation.

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

- Land degradation is often due to a combination of factors.

- Both inadequate soil conservation and overgrazing contribute significantly.

- Correct Answer: Option 3 is correct as both factors are involved.

- Option 4: None of the above

- This option is incorrect as the issues mentioned do significantly contribute to land degradation.