PLEASE HELP! I don't get this at all. the parts are linked, ill upvote the solution too but i need to understand it, please show all working and formulas

You earned 6% on Dotcom stock this year. Last year you earned 18%, two years ago it was 5% and 3 years ago it was 8%. a) Calculate a 4 year holding period return ( 2 marks) b) What was the arithmetic return over the 4 years? (1 mark) c) What was the geometric return over the 4 years? (2 marks) d) If you invested $10,000 at the start (4 years ago), what would be the return? ( 2 marks)