Which of the following was one way that western powers gained the upper hand in muslin regions of the world?

The best answer is, by sending troops to protect their interests. 

Western rulers were skeptical of forming alliances with their Muslim counterparts, and as a result, sought protection of themselves and their assets from within their own resources and by means of trained military personnel. This influx of western military forces caused tension among the Muslim regions and various leaders but was successful in securing the interests of the Western leaders. 

Each mans success depends on his own hard work