option C will be correct.
At level 0 no. of nodes = 2^0
At level 1 no. of nodes = 2^1
At level 2 no. of nodes = 2^2
similarly,At level h-1 no. of nodes = 2^(h-1)
sum them 2^0 + 2^1 + 2^2 ..... + 2^(h -1)
sum = 2^(h +1) - 1
no. of nodes = 2^(h + 1) - 1