The tense used to express an action which was in progress at some point of time limits are not mentioned

The tense used to express an action which was in progress at some poin

1.	The tense used to express an action which was in progress at some point of time limits are not mentioned
A.	Simple past tense
B.	Present continuous tense
C.	Past continuous tense
D.	Present perfect tense
Answer» D. Present perfect tense