Explain how the present value of a sequence of payments is affected by each of the followings (ceteris paribus):

(a) (2.5 marks) An increase in a future expected payment. (b) (2.5 marks) A decrease in the current payment. (c) (2.5 marks) An increase in the expected future nominal interest rate. (d) (2.5 marks) An increase in the current nominal interest rate.