If the speed of light (c) acceleration due to gravity (g) and pressure (p) are taken as the fundamental quantities, then the dimensions of length will be

l∝cαgβpγ⇒L=LT−1αLT−2βML−1T−2γ⇒L=MγLα+β−γT−α−2β−2γ⇒ γ=0,α+β=1 and −α−2β=0⇒ −β=1⇒ β=−1 and α=2 So, l=c2g−1p0Also, we could have done this by taking dimensional formulae for velocity and acceleration and eliminating t.Hence, the correct answer is (1).