Fiona is very angry ________ her boss's decision to sack several members of staff.  about  against  for  by

The correct preposition to fill in the blank is "about."

Explanation

In this context, the phrase "angry about" is commonly used to express strong feelings of displeasure or irritation regarding a specific situation or decision. The other options—"against," "for," and "by"—do not fit appropriately with the expression of anger in this context.

• Angry against implies a more direct confrontation or opposition, which doesn't suit the context as Fiona is reacting to a decision rather than opposing someone directly.
• Angry for is not standard usage. It would imply a reason to be angry on someone else's behalf, which isn't the case here.
• Angry by is also not correct in this context, as it does not align with the common collocation of words.

Final Answer

Fiona is very angry about her boss's decision to sack several members of staff.