Simplify the Following by Combining Like Terms $3.8 x ^ { 3 } - 6.4 x + 11.7 + 1.7 x - x ^ { 3 } - 8.7$

Multiple Choice

Simplify the following by combining like terms.
- $3.8 x ^ { 3 } - 6.4 x + 11.7 + 1.7 x - x ^ { 3 } - 8.7$

A) $1.1 \mathrm { x } ^ { 4 }$
B) $3.8 x ^ { 3 } + 8.1 x + 20.4$
C) $2.8 x ^ { 3 } - 4.7 x + 3$
D) cannot be simplified