Question

The coins which show the Queen’s head on the reverse side, ________________ into circulation in summer 2008. has come came have come had come

Answer 1

The coins which show the Queen’s head on the reverse side, has come into circulation in summer 2008.

Answer 2

The coins which show the Queen's head on the reverse side were introduced into circulation in summer 2008. The correct verb form to complete the sentence is "came." Therefore, the correct sentence is "The coins which show the Queen's head on the reverse side came into circulation in summer 2008."