问题如下：
A LP has committed to invest $200m to a fund with a contractual term of 10 years. Assuming that 20% is contributed in the first year, and 20% of the remaining commitments are contributed in each of the subsequent years. What is the amount contributed in the fourth year?
选项：
A. 20.48m
B. 32m
C. 40m
解释：
A is correct.
Contribution in Year 1: 20%*200m=40m
Contribution in Year 2: (200-40)*20%=32m
Contribution in Year 3: (200-40-32)*20%=25.6m
Contribution in Year 4: (200-40-32-25.6)*20%=20.48m
