Which compound would be expected to show intense IR absorption at 1746 cm^-1?

A) CH₃CH₂OCH₂CH₃
B) CH₃CH₂CN
C) CH₃CO₂CH₂CH₃
D) CH₃CH₂SCH₃

The intense IR absorption at 1746 cm^-1 is characteristic of the carbonyl group (C=O). Choice A and D both contain a carbonyl group, but they also have other functional groups that can absorb IR radiation, so they would not exhibit an intense absorption solely at 1746 cm^-1. Choice B contains a nitrile group (C≡N), which has an IR absorption peak around 2200 cm^-1, not 1746 cm^-1. Only choice C contains a single carbonyl group and no other functional groups that would interfere with its IR absorption in that region, making it the best choice.