The rules of IUPAC followed for hydrocarbon are
a) We will first find out the longest chain of carbon in the given organic compound including triple bond
the root name will be "hex" as number of carbon atoms in longest chain is six.
b) The triple bond will be assigned minimum number locant. the locant will be 2 .
The primary suffix will be "yne"
hence
hex-2-yne
c) we will give locant number to methyl group (present as substituent)
it will be "4"
Thus the completer IUPAC name will be
4-methylhex-2-yne or 4-methyl-2-hexyne [as given in the options]