The correct option is C Anti- Propyl ethyl oxime
In the above structure, ethyl group is present on the same side of the -OH group. Hence, the correct representation is Syn-Ethyl propyl oxime. As the propyl group is present on the opposite side of the -OH group, it can be also represented as Anti- Propyl ethyl oxime.
Hence, the correct answer is both option (a) and (c).