Why/What are Faye and Fifi?

Solution:

The question "Why/What are Faye and Fifi?" asks for the identity or nature of Faye and Fifi. Let's review the provided options:

1. Option 'a' "Valentine's Day!" is a holiday.
2. Option 'b' "It's on 16th June." is a date.
3. Option 'c' "By bus." is a mode of transport.
4. Option 'd' "Because I lost my new watch." is a reason for sadness.
5. Option 'e' "They're fairy penguins." describes a type of creature. If Faye and Fifi are a pair of fairy penguins, this would answer the question.
6. Option 'f' "We can!" is a statement of ability.
7. Option 'g' "It's in the cupboard." is a location.

Based on the options, the most plausible answer is that Faye and Fifi are fairy penguins.

Answer: e They're fairy penguins.