"B. We wanted to try snorkeling, so we signed
<span> up for a class</span>" is the correct answer. The other uses of "so" here are common in speech but not technically correct.
The letter "E" because it happens once a minute (there's 1 E in a minutE) twice in a wEEk (there is 2 E's in week) and once in a yEar (there's 1 E in year)
