Analyze the function $p\left(x\right)=(x+1)(x-6{)}^2$ to determine the intervals of concavity.

• A. Concave up on $(-\infty ,\frac{11}{3})$Concave down on $(\frac{11}{3},\infty )$
• B. Concave up on $(\frac{11}{3},\infty )$Concave down on $(-\infty ,\frac{11}{3})$
• C. Concave up on $(-\infty ,11)$Concave down on $(11,\infty )$
• D. Concave up on $(11,\infty )$Concave down on $(-\infty ,11)$