John Martin Thompson (1829–1907) was a lumberman and civic leader, born in the old Cherokee Nation prior to removal in what is now Cass County, Georgia, USA. He was the son of Benjamin Franklin Thompson, a South Carolinian of Scottish descent, and Annie Martin, a mix blood Cherokee. She was the daughter of Judge John Martin, the first Chief Justice of the Cherokee Nation.
Can we infer the following?
John Martin Thompson's grandfather was a full-blood Cherokee

OPT:
(1). Yes.
(2). It's impossible to say.
(3). No.
The answer is:
(2).