Where did the iron found in earth's core come from?

The iron found in earth's core come from the object of which the earth is made of or through percolation from outer layer of earths to the inner core.

Explanation:

There are several theories which support the point that earth’s core consists of iron ore –

a)It is believed that iron was found in the upper layer of the planet earth and in due course of time this iron percolated to the deep earth core  through percolation channels

b)There is another theory which says that planet earth had formed from a massive rock which consists of iron as its  prime constituent.