The correct IUPAC name of the following compound is:

$\displaystyle 4$-methyl-$\displaystyle 2$-nitro-$\displaystyle 5$-oxohept-$\displaystyle 3$-enal

$\displaystyle 4$-methyl-$\displaystyle 5$-oxo-$\displaystyle 2$-nitrohept-$\displaystyle 3$-enal

$\displaystyle 4$-methyl-$\displaystyle 6$-nitro-$\displaystyle 3$-oxohept-$\displaystyle 4$-enal

$\displaystyle 6$-formyl-$\displaystyle 4$-methyl-$\displaystyle 2$-nitrohex-$\displaystyle 3$-enal