Which of the following is not a valid identifier?
(a) Mybook
(b) @book
(c) _book
(d) book@
Answer:
Checking the options:
- (a) Mybook - It is a valid identifier
- (b) @book - It is not a valid identifier since it starts with a special character.
- (c) _book - It is a valid identifier
- (d) book@ - It is not a valid identifier since it contains a special character.
So, the correct answer is (b) and (d).