If the price of a good X increases, the following can be said about the income and substitution effects of the price increase on the demand for X:
选项：

A:The former is always positive and the latter is always negative.
B:Both can be either positive or negative.
C:While the latter is always negative, the former can be either positive or negative.
D:While the former is always negative, the latter can be either positive or negative.