............., I can say that the dinner was a complete disaster. a) All in all b) As a matter of fact c) Obviously d) In fact

To choose the most appropriate option that fits the sentence, let's analyze each given choice in context:

1. All in all - This phrase generally summarizes a situation, typically with a hint of overall positivity or neutrality. However, in this context where the dinner is described as a "complete disaster," it might not emphasize the negativity effectively.

2. As a matter of fact - This phrase is often used to introduce a statement that emphasizes the truth of what is to follow. It would fit with a factual assertion but could feel awkward in declaring a disaster.

3. Obviously - This term implies that what follows is clear or should be apparent to everyone. While it can suggest something negative, it doesn't introduce the severity of the situation as strongly as desired.

4. In fact - This phrase is used to confirm or clarify a statement, often providing emphasis on the truthfulness of what follows. Given the context of declaring the dinner a complete disaster, this option strongly indicates the speaker's assertion of an unpleasant reality.

Final Answer

The best option is d) In fact, as it effectively emphasizes the severity of the situation being described.