If you mean by controling the bitcoin its price, then it is supply and demand which control it.
Bitcoin is a decentralized currency so every one who run a node, every miner and every holder, are sharing the control in somehow
In theory this is pretty correct, but in practice big miner companies and speculators do have a significant power over the price of the currency and it's own supply and demand. hence we can say they have a level of control over bitcoin.
No one and everyone. But only if you has bitcoin in wallet you have some control. Its the people currecny and there is no control of Govt. Over it.