The correct option is A True
The dissociation of CaCO3 is suppressed at high pressure.
CaCO3(s)⇌CaO(s)+CO2(g)
The reaction proceeds with increase in the number of moles of gaseous species. Hence, the pressure is increased, the equilibrium will shift to left so that the effect of increased pressure is nullified. This is in accordance with Le-Chatelier's principle.