Find the Product $$- 9 k ^ { 1 / 8 } \left( 8 k ^ { 3 / 8 } - 5 k ^ { 3 / 4 } \right)$$

Multiple Choice

Find the product. Assume variables represent positive real numbers.
- $$- 9 k ^ { 1 / 8 } \left( 8 k ^ { 3 / 8 } - 5 k ^ { 3 / 4 } \right)$$

A) $- 72 k ^ { 1 / 2 } - 45 k ^ { 7 / 8 }$
B) $- 72 k ^ { - 1 / 4 } - 45 k ^ { - 5 / 8 }$
C) $- 72 \mathrm { k } ^ { 1 / 2 } + 45 \mathrm { k } ^ { 7 / 8 }$
D) $- 72 k ^ { 3 / 64 } + 45 k ^ { 3 / 32 }$