The answer is C.
A rational number between (√2 and √3) i.e.1.414 and 1.732
(a) √2+√32, which is an irrational number, so it is not a solution.
(b) √2.√32=√62,which is an irrational number, so it is not a solution.
Now, 1.5 and 1.8 both are the rational numbers but only 1.5 lies between 1.414 and 1.732.