Please help to solve this MCQ.

Explanations for each option (why it's true/wrong) are required.

Thanks!

1. In the context of labour-leisure choice, the following statement is true. a) If the labour supply curve is upward sloping, leisure must be a normal good. b) If the endowment income effect is positive, the law of demand will hold for leisure. c) If leisure is a Giffen good, then leisure must also be a normal good. d) The substitution effect for leisure is always positive