Select the letter of the INCORRECTLY written sentence.

a.
My friend Alexis toured Greenfield Village, a well-known historical attraction in the area.

b.
My friend Alexis toured Greenfield Village. A well-known historical attraction in the area.

c.
My friend Alexis toured Greenfield Village. It is a well-known historical attraction in the area.

d.
My friend Alexis toured Greenfield Village; it is a well-known historical attraction in the area.