State whether each of the following is true, false or uncertain and explain why.

a)If a good is a normal good. then the substitution effect and the income effect are of the same sign.

b)If a consumer has Cobb-Douglas preferences, it is possible for one of the goods to be a Giffen good.

c)If a consumer has quasi-linear preferences over two goods, then her consumption of neither good depends on her level of income.