Here are the answers for each question based on the images described:

1. **B. weather forecast** - This is a program that describes the weather.
2. **A. comedian** - A person who acts in a comedy is a comedian.
3. **A. sitcom** - Sitcoms are often funny and colorful.

For the last question:

- The answer would likely be **D. programmes**, as they refer to various entertainment options on TV.

So the corresponding letters to circle would be:
1. B
2. A
3. A
4. D