Concurrent power are those powers practiced and executed at the same time, in a common area and within the same group of people by the State and Federal government in a jointly manner. Also, concurrent powers deal with political powers that are used by the state and at the same time, by Federal governments.
Concurrent powers are very useful for the different levels of Government because they allow them to maintain people´s safety, stop criminal acts, improve the economy and at the same time, to punish and stop criminal actions.
The correct answer will be an example of concurrent power is when a federal law enforcement agency helps a state police. This is a classical example of both agencies acting together for the common good of their citizens.