Nielson is a contract-based employee working in one of the government departments. The contract period started from June 1^st, 2018 to May 31^st, 2020. During the year ended March 31^st, 2020, he received the following from his employer (the government):

12. Annual Salary (from June 1^st, 2018 to May 31^st, 2020): $480,000
13. Contract gratuity: 15% of his total contract salary upon completion of the 2-year employment contract
14. The employer deducted 5% of Nielsons monthly salary as his contribution to the MPF retirement scheme

Other information:

12. Nielson paid the following
    1. Cash donations to approved charitable organizations $5,000
    2. Self-education expenses $2,000
13. Nielson and his wife have a 2-year old son.
14. Nielsons wife is a full-time housewife.
15. Nielsons mother-in-law aged 57 is living with him.
16. Nielson bought an apartment under a mortgage loan from bank. The annual interest payment for the mortgage is $45,000.
17. Nielson purchased a health insurance package which is a certified plan of Voluntary Health Insurance Scheme at a premium of $4,000 per year which covers the period from April 1^st 2019 to March 31^st, 2020.
18. Nielson select to have the contract gratuity related back

Question

1. Compute the amount of contract gratuity to be assessed in each of the years of assessment concerned. (10 marks)
2. Compute Nielsons net assessable income and the salaries tax payable for the year of assessment 2019/20. Which tax rate, standard or progressive, will he choose to pay the tax? (25 marks)