A, B and C are partners in a firm sharing profit and losses in the ratio of 4:3:2. B decides to retire from the firm. Calculate new profit-sharing ratio of A and C in the following circumstance:

a. If B gives his share to A and C in the original ratio of A and C.

b. If B gives his share to A and C in equal proportion.

c. If B gives his share to A and C in the ratio of 3:1.

d. If B gives his share to A only.