A punctuation question with the same transition in every choice tests where sentences end or continue. A transition can't join sentences on its own, so cover the transition and split the text to see whether each side stands alone. Look for words that make a part depend on the rest. A semicolon joins two complete sentences, while commas set off a transition inserted as an aside. Check the sentence structure first, because familiar punctuation can hide an incomplete sentence.
Hints
- Hint 1
Cover however and read both sides of the blank. Look for the subject and main verb in each part, using the words each choice adds.
- Hint 2
Look at the part beginning with because. Does it stand alone, or does it give a reason for the words before it?
Step-by-step
Cover and split
Step 1Read both sides
Cover however in the choices, but keep because in place, since this question asks where the sentence can break. Before the blank, That regularity is becomes a full sentence when we add deceptive: it has a subject and a main verb. What about minute variations in the tension of the wool cause corresponding shifts? That side has a subject and a main verb, since the variations cause the shifts, but we still need to check what because does.
- Step 2
Test because
Does the part beginning with because stand alone? No: because makes it a dependent clause, a group of words that needs the rest of the sentence to finish its thought. The corresponding shifts in the diamonds' widths explain why the apparent regularity is deceptive, so the reason belongs with the claim that the regularity is deceptive. A semicolon must join two complete sentences. The version with a semicolon before however and the version with a semicolon after it both leave that reason as a fragment, an incomplete sentence.
- Step 3
Set off the transition
How should however sit inside this sentence? It contrasts the claim that the regularity is deceptive with appear mechanically uniform in the opening sentence. However needs a comma on each side inside this sentence, so the version with no comma after it leaves the pair unfinished. The completion deceptive, however, because adds both commas without breaking the sentence. Choice B.