Which area has the most accessible oil reserves? caspian sea siberia arctic coast lake baikal

I think Caspian sea, sncce people live around here and infrastructure is already developed. 

Siberia Arctic coast

Explanation:

The east Siberian sea is the marginal sea in the arctic ocean and is located in the arctic capes and in the Siberia in the south, has a surface area of about 987,000 km square and remains frozen through the year.  The sea is least populated and least salinity and the south of the sea coast has gold mines located near the  Pevek, and it's estimated that arctic has 90 billion barrels of oil, which is 6% of the world's oil reserves trapped under the layers of ice and snow. Other island named as the Sakhalin is one of the oil rich reserves n the far east.

The name may be in importnce  to them

The answer for your problem would be a. 7