Acetanilide is a compound formed by the reaction of aniline with acetic anhydride. The reaction is an example of acetylation, where an acetyl group -COCH\(_3\) from acetic anhydride attaches to the nitrogen of the aniline molecule.
The general reaction for the preparation of acetanilide is:
\[
\text{Aniline} + \text{Acetic anhydride} \rightarrow \text{Acetanilide} + \text{Acetic acid}
\]
Thus, the correct answer is Aniline and acetic anhydride.