The correct option is A M1>M2
First we derive an expression for density of a gas.
Density = mass(w)volume(V)
but we know that PV = nRT
now n = wM where M is molecular weight
So, PV = wMRT
this gives wV=PMRT = density = d
clearly graph of pressure vs density is a straight line with slope = RTM
steeper the line, more is the slope and so less is the mass (at a given temperature)
so here M1>M2