Problem: How does the sentence end?

Steven always calculate the risks before they invest but Benjamin doesn't as
Answer: Steven is careful.

Problem: How does the sentence end?

Mark never pays with his debit card and uses the credit card instead, because the
Answer: debit card is less safe.

Problem: How does the sentence end?

Betty but not Victoria had to go for a screening because
Answer: Betty noticed an unusual growth behind their ear.

Problem: How does the sentence end?

In choir, Laura is taking voice lessons from Erin, so it's likely
Answer:
Erin is the teacher.