(d) 37.5%
Let the price of the commodity be Rs x and its consumption be y. Then
Expenditure = Rs xy
Increased price = Rs \(\frac{160}{100}\)x = Rs 1.6x
Expenditure remaining the same = Rs xy
\(\therefore\) Reduced consumption = \(\frac{Xy}{1.6X}\) = \(\frac{10y}{16}\) = \(\frac{5}{8}\)y
% reduction in consumption = \(\frac{y-\frac{5}{8}y}{y}\)x 100
= \(\frac{3}{8}\)x 100% = 37.5%