It is "M".
Bolivia and Brazil share a border.
border
Yes, "border" can be a verb, meaning to form or be on the border of something. For example, "The field borders the forest."
Brownsville (TX)
The paronychium is the soft tissue around the nail border.
edge:a line or border at which a surface terminates
Which state has a longer border with Mexico, Texas or New Mexic?
Abut
To adjoin; to border on; tobe near to., To associate intimately with.
One way is 2 is doing numbers and letters together (A1 A2)
The border between Poland and Germany was often referred to as the Oder-Neisse Line.
He is the postman carrying letters.