What is the name of king mentioned in Iron Pillar Inscription of Mehrauli?

Who is the author of Allahabad Pillar Inscription?

The Allahabad Pillar inscription is associated with which one of the following?

An inscription by which of the following is found on the pillar containing Prayag Prasasti of Samudragupta?

The Eran inscription belonged to the reign of

From which inscription it is known that Skandagupta defeated Hunas?