Solution

Option (a): \( \sqrt{3} + 1 \)

✘ Irrational

\( \sqrt{3} \) is irrational, so adding 1 keeps it irrational.

Option (b): \( \pi \)

✘ Irrational

\( \pi \) is non-terminating and non-repeating.

Option (c): \( 2\sqrt{3} \)

✘ Irrational

Multiplying an irrational number by a non-zero rational number remains irrational.

Option (d): \( 0 \)

✔ Rational

\( 0 \) can be written as \( \frac{0}{1} \), hence it is rational.

Final Answer

✔ Correct option: (d) \( 0 \)