Let $f ( x , y ) = x y$ , and Let

Multiple Choice

Let $f ( x , y ) = x y$ , and let $R = \{ ( x , y ) \mid 0 \leq x \leq 1,0 \leq y \leq 1 \}$ . Let R be partitioned into four subrectangles by the lines $x = \frac { 1 } { 2 }$ and $y = \frac { 1 } { 2 }$ , and let $\left( x _ { i } ^ { * } , y _ { j } ^ { * } \right)$ be the upper left corner of Rij. Calculate the double Riemann sum of f.

A) $\frac { 3 } { 16 }$

B) $\frac { 1 } { 4 }$
C) $\frac { 5 } { 16 }$
D) $\frac { 3 } { 8 }$
E) $\frac { 7 } { 16 }$
F) $\frac { 1 } { 2 }$

G) $\frac { 9 } { 16 }$

H) $\frac { 3 } { 4 }$