C) vertical stretch by a factor of 5 about the line y=6
Explanation
Step 1
[tex]\begin{gathered} y=2x+6\rightarrow transormation\rightarrow y=10x+6 \\ \text{analyze} \\ x,\text{ from 2x to 10x} \\ \text{factor of x = }\frac{10x}{2x} \\ factor\text{ of x=5} \end{gathered}[/tex]when the variable ( x in this case) is multiplied by a factor greater than 1, then it is a
C) vertical stretch by a factor of 5 about the line y=6