ANS:A - rapidly first and then slowly.

With an increase in steam pressure, its specific volume decreases rapidly first and then slowly. This phenomenon occurs because at lower pressures, steam behaves like an ideal gas, and changes in pressure have a more significant impact on its specific volume. As pressure increases, steam undergoes compression, resulting in a rapid decrease in specific volume initially. However, as pressure continues to increase, steam approaches the saturation point, where it transitions into a saturated vapor or liquid phase. At this point, further increases in pressure have less effect on the specific volume, leading to a slower decrease. Therefore, the specific volume of steam decreases rapidly at lower pressures and then decreases more gradually as pressure continues to rise.