Right option is (d) 6
Explanation: We know that according to laws of exponents, 1/18^-1/2 = 18^1/2
Hence, (2)^1/2/(18)^-1/2 =(2)^1/2 (18)^1/2
According to laws of exponents, (a^m)*(b^m) = (ab)^m
Applying that rule here, (2)^1/2 (18)^1/2 = (2*18)^1/2
= (36)^1/2
= 6.