Perform the Indicated Operation $$\frac { 4 } { 10 x z ^ { 2 } } + \frac { 3 } { 10 x z ^ { 2 } }$$

Multiple Choice

Perform the indicated operation. Simplify if possible.
- $$\frac { 4 } { 10 x z ^ { 2 } } + \frac { 3 } { 10 x z ^ { 2 } }$$

A) $\frac { 10 \mathrm { xz } ^ { 2 } } { 7 }$
B) 1
C) $\frac { 7 } { 20 \mathrm { xz } ^ { 2 } }$
D) $\frac { 7 } { 10 \mathrm { xz } ^ { 2 } }$