Njapan, who was the first to effectively use firearms (guns and cannons) in battle

Oda Nobunaga, who was a feudal lord of Japan in the late 16th century, was the first to effectively use firearms on the battlefield in Japan. He attempted to unify Japan during part of the Sengoku period by defeating many opponents and seizing the imperial capital Kyoto. He was known to primarily use a tanegashima firearm which is a type of matchlock gun.

The answer is a c b d a c b d