Which answer choice shows the correct capitalization for the proper adjective in the following sentence? the massive peaks of the alps are a central part of the european continent. a)the massive peaks of the alps are a central part of the european continent. b)the massive peaks of the alps are a central part of the european continent. c)the massive peaks of the alps are a central part of the european continent. d)the massive peaks of the alps are a central part of the european continent.