Brian and Daniel are civil partners. They were both born in 1976. Brian's total income for 2020-21 is £30,000 and Daniel's total income for the year is £10,000. None of their income is derived from savings or dividends.

(a) Calculate their income tax liabilities if Daniel does not make an election to transfer part of his personal allowance to Brian.

(b) Calculate their income tax liabilities if Daniel does make the election.

(c) How would the situation change if Brian's total income were £60,000?