By 900 ce, kiev controlled the large area between the baltic sea and the black sea, which made kiev
a. difficult to rule.
b. difficult to defend.
c. a very powerful state.
d. want to expand even further.

The correct answer is C) a very powerful state.

By 900 CE, Kiev controlled the large area between the Baltic Sea and the Black Sea, which made Kiev a very powerful state.

Kiev was a dominant and powerful empire in medieval times. It has an economic and political dominance over other territories. The Vikings from Sweden migrated to this area of Kiev in what today is Ukrania. Indeed, Kiev is today’s capital of Ukrania. Viking King Rurik established a settlement in this region. In 980 CE, Vladimir the Great reigned a prosper territory in peace that controlled the large area between the Baltic Sea and the Black Sea, which made Kiev a very powerful state.  

the correct answer is to reduce tax

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.