Use the Product Rule to Simplify the Expression $y \cdot y ^ { 9 }$

Multiple Choice

Use the product rule to simplify the expression.
- $y \cdot y ^ { 9 }$

A) $2 \mathrm { y } ^ { 10 }$
B) $2 \mathrm { y } ^ { 9 }$
C) $y ^ { 9 }$
D) $y ^ { 10 }$