Calculate the married couple's allowance available to the following couples in 2021-22, assuming that they were married before 5 December 2005 and that they have not elected for MCA to be claimed by the spouse with the higher net income: 

(a) Husband born 1931, income £19,900; wife born 1932, income £29,500 

(b) Husband born 1929, income £30,440; wife born 1934, income £10,070 

(c) Husband born 1934, income £36,800; wife born 1939, income £20,000 

(d) Husband born 1936, income £18,600; wife born 1933, income £46,700.

In each case, the stated income figure is the adjusted net income.