please help me find this answer i really dont know what to do for this question. more importantly i need help with determining what functions i should use to find this answer using excel.

A systems engineer who invested wisely can retire now because she has $2,000,000 in her self-directed retirement account. Determine how many years she can withdraw ( a ) $100,000 per year, or (b)$150,000 per year (beginning 1 year from now) provided her account earns at a rate of 5% per year. (c) Explain why the increased annual withdrawal from $100,000 to $150,000 per year is important. Select the correct answer. a) Infinity, b) 22.5 a) 22.5 , b infinity a) Infinity, b) Infinity a) 22.5 , b) 22.5