Which of the following is true? Select one: O A. A subcover of a cover (Ea)acI of M is a cover (Sa)acI of M such that Sa C En for all a e I. O B. A cover of M is a collection of open sets (E,)act such...

Extracted text: Which of the following is true? Select one: O A. A subcover of a cover (Ea)acI of M is a cover (Sa)acI of M such that Sa C En for all a e I. O B. A cover of M is a collection of open sets (E,)act such that M C U E, ael O C. An open cover of M is a collection (E.)act of subsets E, of M such that U E, is an open subset of M. O D. An open cover (E,)ael of M is called finite if the index set I is finite.