I think it's one of the toughest ones to do under 2 minutes just for the sheer amount of calculations required. With very imprecise calculation I get that in the scenario 1 the person would get ~780k: ~260k at the end of Year 3, then 310k after adding 50k, by the end of Year 4 = 330k, and the amount doubles in ~13 years (72/rate = time to doubling), so 660k at the end of Year 17. Then again an imprecise calculation of +35-40k in the last 4 years each year yielding ~780k.
The same logic applies to the second calculation, but with the different numbers. At the end of Year 5 he would get ~140k, and we see that he has to increase the amount of money almost 5,5 times in 15 years.
We can definitely forget about C (would be too much) and E (too little), so the real choice is between A,B, and D. I would go anc check D first (try to see how the numbers are growing) to see that it will be too much - I had to calculate to year 13 to understand it, thus leaving B as a correct choice.
It took me well over 6 minutes to do it, and unfortunately I don't really see an easier approach. As always, great question
Bunuel!