B. The Himalayans separate India from the rest of Asia. One way to remember is that China and India fought a war in 1962, and they both have troops up guarding the McMahon Line to this day. India and China are in a superpower competition. China builds dams which impacts India's rivers, increasing the potential for hostilities. Adding to their tensions is the fact that China just made friends with Pakistan. It's very complicated and it involves every nation in Asia. If you remember that the Himalayans are an important barrier between these two countries, you're good to go.