A.
In fact, most of the less developed areas are rich in natural resources, \r\nyet have great potentials for development.
B.
In fact, most of the less developed areas are rich in natural resources, \r\nand have great potentials for development.
C.
In fact, most of the less developed areas are rich in natural resources, \r\nbut their development potential is very great.
D.
In fact, most of the less developed areas are rich in natural resources, \r\nas their development potential is very great.