单选题 One year ago, an investor made five separate investments with the invested amounts and returns shown below. What is the arithmetic and geometric mean return on all of the investor's investments ?

A、 Investment
B、 Invested Amount
C、 Return(%)
D、 A
E、 10000
F、 12
G、 B
H、 10000
I、 14
J、 C
K、 10000
L、 9
M、 D
N、 20000
O、 13
P、 E
Q、 20000
R、 7

【正确答案】 C

【答案解析】Arithmetic Mean: 12 + 14 +9 + 13 +7 =55; 55/5 = 11 ; Geometric Mean: