In the following questions, a sentence has been divided into four parts and marked a, b, c and d. One of these parts contains a mistake in grammar Idiom or syntax. Identify that part and mark it as the answer.

A. The train is unusually late today

B. for it has been announced just now

C. that it will arrive in a hour

D. on platform number three

Please do not use chat terms. Example: avoid using "grt" instead of "great".