A punctuation question with the same transition in every choice tests whether the surrounding words form one sentence or two. Cover the transition and test whether each side can stand alone by finding its subject and main verb. A transition interrupting a clause takes paired commas; between full sentences, it takes a period or semicolon on one side and a comma on the other. Use grammar first, because familiar punctuation patterns can hide a broken sentence.
Hints
- Hint 1
In the sentence beginning with the animals’ repeated approach, find the main subject and verb with however covered.
- Hint 2
Look at the clause beginning with where. Is it the main thought, or is it describing the trees?
- Hint 3
Can the words on either side of the blank stand alone, or does one side need words from the other?
Step-by-step
Cover and split
Step 1Find the main subject and verb
Cover however and read through the blank with calling, which all the choices share, to see whether we have one sentence or two. What is being said about The animals’ repeated approach? The approach suggests something, so approach is the main subject and suggests is its verb. The words starting with where other bats are form a clause, a group with its own subject and verb, that describes the trees. The verb are calling belongs to that description, so it doesn't finish the main thought about the approach.
- Step 2
Test whether the split works
Can either side now stand alone? Before the blank, the long subject describes the approach but never says what it does; after the blank, suggests that social cues also guide their choices has the main verb but no subject of its own. A semicolon must separate two complete sentences, so it can't cut this subject away from its verb. The version with a semicolon before however leaves the approach without its main verb, and the version with a semicolon after however makes the same break.
- Step 3
Set off the transition
How do we set off however inside this sentence? A transition interrupting a clause takes a comma on each side, so it can interrupt the thought without breaking it apart. The version without a comma before however marks only the end of the interruption. The commas in calling, however, let the subject connect to suggests while however challenges the earlier claim of smell alone. Choice B.