Final answer:
The sentence is incorrect because the use of the comma is unnecessary. Subjects and predicates, in this case 'The man in the red coat' and 'will definitely miss the bus' respectively, do not need to be separated by a comma. The correct sentence is 'The man in the red coat will definitely miss the bus.'
Step-by-step explanation:
The sentence 'The man in the red coat, will definitely miss the bus.' is incorrect due to inappropriate use of the comma. In this sentence, 'The man in the red coat' is a complete subject and 'will definitely miss the bus' is a complete predicate. According to English grammar rules, a comma is not needed to separate the subject from the predicate. The correct sentence should be 'The man in the red coat will definitely miss the bus.'
Learn more about Comma Usage