I need a thorough and comprehensive explanation for PART C and D. Thank you.

3. During 2015, Nilsen Company started a construction job with a contract price of 1,600,000. The job was completed in 2017. The following information is available. Costs incurred to date Estimated costs to complete Billings to date 2015 400,000 600,000 300,000 2016 825,000 275,000 900,000 2017 1,070,000 0 1,600,000 S4/09/20 Page 1 Collections to date 270.000 810,000 1,425,000 a) Compute the amount of gross profit to be recognized each year, assuming the percentage-of-completion method is used. (7.5 marks) b) Prepare all necessary journal entries for 2016. (7.5 marks) c) Compute the amount of gross profit to be recognized each year, assuming the cost-recovery method is used. (7.5 marks) d) According to you, which one is better to used for company