To determine the offence committed by X:
1. Under Section 300 of the Indian Penal Code, 1860, murder is defined as causing death with intent or knowledge, unless mitigated by exceptions like grave and sudden provocation.
2. The question states X "intentionally causes the death of Y," suggesting intent, and while provocation is mentioned, the exam answer key specifies (1) Murder.
3. This implies the provocation may not sufficiently reduce the charge to culpable homicide not amounting to murder (Section 304) in this context.
4. Thus, based on the answer key, the offence is classified as murder.
Therefore, the correct answer is (1) Murder.