The names of some compounds are given. Which one not in the `IUPAC` system?

Options

A. `underset("3-Methyl-2-butanol")(CH_(3) - underset(OH)underset(|)(OH) - underset(CH_(3))underset(|)(CH)-CH_(3))`
B. `underset("4-Methyl-2-pentyne")(CH_(3)-C-=C-CH(CH_(3))_(2))`
C. `underset("2-Ethyl-3-methyl-but-1-ene")(CH_(3)-CH_(2)-underset(CH_(2))underset(||)C-underset(CH_(3))underset(|)CH-CH_(3))`
D. `underset("3-Methyl-4-ethyl heptane")(CH_(3)-CH_(2)-CH_(2)-underset(CH_(2)CH_(3))underset(|)(CH)-overset(CH_(3))overset(|)CH-CH_(2)CH_(3))`

Answer

D

Explanation

Ethyl should come before methyl.