The triple alliance and the triple entente contributed to the start od world war 1 by a, failing to include germany and france as members. b, threatening countries in the western hemisphere. c, allowing japanese aggression in korea d, increasing tentions between european contries

The Triple Alliance and Triple Entente are two opposing alliances that triggered in the start World War I. The formation of these two alliances heightened the tensions between European countries. The Triple Alliance which is composed of Germany, Austria-Hungary, and Italy had a conflict with Triple Entente members - France, Russia, and Great Britain. Germany and Russia, during that time, had a great interest towards the Balkans. This is one of the reasons of the occurrence of World War I. So, the answer to the question is letter d. increasing tensions between European countries.

Primary sources are usually  more accurate and are written by someone who experienced it or witnessed it. secondary sources are those who heard of it after the fact that can lose details and or twist the event in a light that benefits them.