Select the best IUPAC name for the molecule below: a. E-4-(5-isopropyl-2-methylphenyl)but-3-en-2-one b. E-4-ispropyl-2-(3-oxo-but-1-ene)toluene c. E-4-(3-isopropyl-6-methylphenyl)but-3-en-2-one d. E-4-(5-isopropyl-2-methylphenyl)but-1-en-3-one