Choose from options: Determine if the sentence is true based on the text below:
Kohl joined the Christian-Democratic Union (CDU) in 1947, but was unhappy while he was a part of it. 

Kohl participated in the late stage of WWII as a teenage soldier. He joined the Christian-Democratic Union (CDU) in 1947.
OPT:
 (a). Yes.
 (b). It's impossible to say.
 (c). No.
(b).