High-minded. As used in Middle English, high-minded means haughty or proud. Today's meaning is noble in thought or sentiment.

amelioration

pejoration

generalization

specialization

I would say the correct answer is A. amelioration. It means improving the connotation of a word, or elevating it from neutral or negative (pejorative) to positive. The word "high-minded" had a negative connotation, but today its use has changed, and it has a positive connotation.