Sum of Binomial Coefficients of Odd Numbered Terms

Q. If $n$ is a positive integer, then $(\sqrt{3}+1{)}^{2n}-(\sqrt{3}-1{)}^{2n}$ is :

1. an irrational number
2. an odd positive interger
3. an even positive interger
4. a rational number other than positive integers

Q. In the expansion of $(1+x{)}^{50}$ the sum of the coefficients of odd powers of x is

1. 0
2. $2^{49}$
3. $2^{50}$
4. $2^{51}$

Q. In the expansion of $(1+x{)}^{50}$, the sum of the coefficient of odd powers of x is

1. $2^{49}$
2. \N
3. $2^{50}$
4. $2^{51}$