Select the correctly punctuated sentence. Will we ever get there? Sandy asked fretfully.

The correctly punctuated sentence is the first one "Will we ever get there?". It's a direct question, so the question mark is obligatory at the end and it replaces a period in case the sentence finishes there.

The second part "Sandy asked fretfully", must be preceded by a comma because what comes after is the person who came up with the question. However, if it is a quoted question (it doesn't seem to be the case here), which end in mid sentence, the question mark replaces a comma.