Before version _______, capped collections did not have an _id field.
A. 2.1
B. 2.4
C. 3.0
D. 2.2
Answer:A
Before version _______, capped collections did not have an _id field.
A. 2.1 B. 2.4 C. 3.0 D. 2.2
Explanation:In version 2.2 and newer, capped collections do have an _id field, except those in the local database. 2. Point out the wrong statement :