The british encouraged arab nations to revolt against the ottoman empire because the

Ottoman empire had allied itself with Germany in World War I

Explanation:

In 1915, the British needed the help of the Arabs in defeating the Ottoman Empire in World War I, they promised the Arabs that if they rebelled against The Ottoman Empire (which had sided with Germany in the war), that they would get their own independent state.

However the Arabs fought and died for the British, thinking that they would gain their independence as a reward for their sacrifice. Yet what ended up happening instead, is that the British and French marched into their territory and claimed the remains of empire for themselves.

the fact that could also be added to column b is that during world war ii, specifically between the years 1941 and 1945, japan expanded its territory towards the indonesian territory in what was known later as part of the "pacific war". in that time, japan could conquer the philipines, singapore,   borneo, central java, malang, cebu, sumatra and various other islands of the area, therefore expanding its territory for a brief period of time.

the answer is b: an economic crisis throughout the country.