While measuring the speed of sound by performing a resonance column experiment, a student gets the first resonance condition at a column length of 18cm during winter. Repeating the same experiment during summer, she measures the column length to be xcm for the second resonance. Then
(a) 36 > x > 18
(b) 18 > x
(c) x > 54
(d) 54 > x > 36.
