What as-path access-list regular expression should be applied on R2 to only allow updates originated from AS65501 or autonomous systems directly attached to AS65501?

Refer the Exhibit. What as-path access-list regular expression should be applied on R2 to only allow updates originated from AS65501 or autonomous systems directly attached to AS65501?

A.
_65501+[0.9]$

B.
^65501_[0-9]*$

C.
_65501_*$

D.
_65501_.*

E.
[0-9]*+65501_+[0-9]$

F.
^65501_*$