The changes that take place during the process of consolidation of a saturated clay would include

ANS:D - a decrease in pore water pressure and an increase in effective pressure

1St stage immediately during consolidation, there will be an increase in pore water pressure, effective stress will be zero.
2ND stage - pore water pressure starts to decrease and effective pressure starts to increase.
3Rd stage- after the consolidation pore water pressure becomes zero and effective stress increases.

But during all the three stages TOTAL STRESS remains constant.