Which AS-PATH access-list regular expression should be applied on R2 to allow only updates that originate from AS-65001 or an AS that attaches directly to AS-65001?

Refer to the exhibit.

Which AS-PATH access-list regular expression should be applied on R2 to allow only updates that originate from AS-65001 or an AS that attaches directly to AS-65001?
A. ^65001_[0-9]*$
B. _65001^[0-9]*
C. 65001_[0.9]$
D. ^65001_*$