$\textbf{Answer}$

$W2$

$\textbf{Analysis}$

The pattern in the numeric part is obvious: skipping the next number in line. The trick is in the letter part. It does not appear to have anything to do with the alphabetic sequence. Therefore, it must be something else. One commonly used scheme in brain teasers is the initials of some words. In this case, they are the initials of the weekdays: Friday, Sunday, Tuesday, Thursday, Saturday, Monday, which also skip the next day in line. Hence, the next term should be Wednesday the $2^{nd}$.