[" (68) 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 "x" cm for the second "],[" resonance.Then,"],[[" (a) "18>x," (b) "x>54],[" (c) "54>x>36," (d) "36>x>18]]