$ f1=2^n, f2=n^(logn) , f3=n^√n , f4=n^2 $
lets check for large value of n i.e $2^6$
$f1=2^(64), f2=(2^5)^6, f3=(2^6)^8, f4=(2^(12)) $
$f1= 2^(64),f2=2^(30) f3=,2^(48),f4=2^(12) $
Increasing Order of Asymptotic complexity:
f4<f2<f3<f1
Hence B is the correct option.