2. A table of positive integers is shown in Table 1 (the number of elements in the next row is twice the number of elements in the previous row). Then the 5th number in the 8th row is ( ).
(A) 68
(B) 132
(C) 133
(D) 260
Table 1
\begin{tabular}{|c|cccc|}
\hline First Row & 1 & & & \\
\hline Second Row & 2 & 3 & & \\
\hline Third Row & 4 & 5 & 6 & 7 \\
\hline Fourth Row & $\cdots \cdots$ & \\
\hline
\end{tabular}
2.B.

From the problem, we know that the number of digits in the $n$-th row is $2^{n-1}$, and starting from the second row, the first number of each row is $2^{n-1}$. Therefore, the first number in the eighth row is $2^{7}=128$. Hence, the fifth number in this row is 132.