What is the smallest particle that has all the properties of a specific element?

A.among Russia, Britain, and the shah of Persia

Explanation:

In 1907. The Imperial ambitions of Britain and Russian were conciliated, as a division took place, the north of (Today Iran) became under influence of Russia, the south becoming influenced by England and in the middle the formation of a puppet state that was favorable to both Empires.

The civil uprisings of 1905, posed some treats to the interests of these nations that would not encourage liberal reforms in the country. Neither of them accepted the social changes and then resolved to form The Anglo Russian Entente, in 1907, the frontiers are then shaped to promote a region that otherwise would have turned unfavorable to the status quo.

Under the argument of a neutral zone, the middle of Persia remained in control together with some foreign delegates that always promoted traditional policies.

See the image below for reference: