Ans: C
Note that $T(n+1) = T(n) + (2n+3)$ for $n \ge 1$. Hence, we have
Note that $T(n+1) = T(n) + (2n+3)$ for $n \ge 1$. Hence, we have
$\begin{array}{rcl}
T(4) & = & T(3) + (2(3) + 3) \\
& = & 15 + 9 \\
& = & 24 \\
T(5) & = & T(4) +(2(4) + 3) \\
& = & 24 + 11 \\
& = & 35 \\
T(6) & = & T(5) + (2(5) + 3) \\
& = & 35 + 13 \\
& = & 48
\end{array}$
