Add or Subtract $$10 \sqrt [ 4 ] { x ^ { 7 } } - 3 x \sqrt [ 4 ] { x ^ { 3 } }$$

Multiple Choice

Add or subtract. Assume all variables represent positive real numbers.
- $$10 \sqrt [ 4 ] { x ^ { 7 } } - 3 x \sqrt [ 4 ] { x ^ { 3 } }$$

A) $13 \sqrt[4]{x^{3}}$
B) $7 x \sqrt[4]{x^{3}}$
C) $10 \sqrt[4]{x^{7}}-3 x \sqrt[4]{x^{3}}$
D) $7 \times \sqrt[4]{x^{7}}$