Good morning, please solve

18. (a) Mr. Singh purchased a residential property in Mumbai in the year 1994 for 5,75,000. In 1999-2000, he remodeled the property by spending 2,50,000. On 1.4.2004 he entered into an agreement with Mr. Vinay for sale of the property for 38,52,000 (the fair market value as on 1-4-2001 is 86,00,000) and received an advance of 25,000. Due to inability of Mr. Vinay to pay sale consideration in due time, Mr. Singh cancelled the agreement and forfeited the advance money received from Mr. Vinay. During the financial year 2004-05, he spent 56,500 to construct an additional room in the house. The house was sold on 5th September 2019 for 36,82,605. He purchased a new flat for his residence on 30-4-20 for 5,00,000. You are required to compute taxable capital gains of Mr. Singh for the assessment year 2020-21. [CII for 2003-04: 109; 2004-05:113; 2019-20: 289] (b) How can Mr. Singh ensure that the exemption u/s 54 is never revoked? [8+2]