Here the bases of numbers can't be made same so making their powers equal
1. $2^{\frac{1}{2}} = 2^{({6})\frac{1}{12}} = 64^{\frac{1}{12}}$
2. $3^{\frac{1}{3}} = 3^{({4})\frac{1}{12}} = 81^{\frac{1}{12}}$
3. $4^{\frac{1}{4}} = 4^{({3})\frac{1}{12}} = 64^{\frac{1}{12}}$
4. $6^{\frac{1}{6}} = 6^{({2})\frac{1}{12}} = 36^{\frac{1}{12}}$
5. $12^{\frac{1}{12}}$
Here clearly we can see $3^{\frac{1}{3}} = 3^{({4})\frac{1}{12}} = 81^{\frac{1}{12}}$ is the Largest value.
Hence (B) $3^{\frac{1}{3}}$ is the Answer.