The next term of the sequence 1, 2, 5, 26, … is:

677
The series is based on following pattern :
$latex \left ( 1 \right )^{2}+1=2$
$latex \left ( 2 \right )^{2}+1=5$
$latex \left ( 5 \right )^{2}+1=26$
$latex \left ( 26 \right )^{2}+1=677$
Therefore, the next number of this series will be 677.
Hence option [B] is correct.