What is the IUPAC name of the given compound?

The correct answer is option 1. 5,6-diethyl-3-methyldec-4-ane.

The longest straight chain contains 10 carbon atoms, but the numbering will start from the side from which the double bond is nearest.

There are three side chains: one methyl group at 3rd carbon, two ethyl groups at the 5th and 6th carbon respectively.

There is a double bond at the 4th carbon, thus the name of the compound will be 5,6-diethyl-3-methyldec-4-ane.