A. since
B. for
C. from
D. so
Past perfect continuous tense is used when a work is being continued for some time from the past. has been distributing is past perfect continuous and for is the correct preposition to be used.
A. since
B. for
C. from
D. so
Past perfect continuous tense is used when a work is being continued for some time from the past. has been distributing is past perfect continuous and for is the correct preposition to be used.