The correct answer is Option C.
DETERIORATION means decline or gradual worsening. In the given sentence, the writer is describing how role of women changed for the worse after the Vedic age.
Thus, DETERIORATION is the correct answer.
The remaining options are incorrect:
Option A: FALL means to suddenly go on the ground in downward motion.
Option B: DEGENERATION means the process of declining.
Option D: DOWNFALL means the loss of power.
These words are not correctly appropriate and relevant.
Thus Option C is the correct answer.