Considering the context presented, which statement is CORRECT? a. The use of ObjectIds for the _id field in MongoDB documents is not necessary. b....

Considering the context presented, which statement is CORRECT?

a. The use of ObjectIds for the _id field in MongoDB documents is not necessary.
b. The ObjectId() function returns the string hexadecimal representation of the object.
c. The ObjectId.getTimestamp() function returns the timestamp portion of the ObjectId() as a Date.
d. All MongoDB operations are atomic at the level of a single document.
a. The use of ObjectIds for the _id field in MongoDB documents is not necessary.
b. The ObjectId() function returns the string hexadecimal representation of the object.
c. The ObjectId.getTimestamp() function returns the timestamp portion of the ObjectId() as a Date.
d. All MongoDB operations are atomic at the level of a single document.