Option 1: elaborate -> means detailed or intricate, not the opposite of lavish.
Option 2: excessive -> means too much or extreme, which is similar to lavish, not opposite.
Option 3: hectic -> means busy or chaotic, unrelated to the concept of lavish spending.
Option 4: frugal -> means economical and avoiding waste, the direct opposite of lavish.
Hence, Option 4: frugal -> "Lavish" means extravagant and spending abundantly, while "frugal" means being economical and spending carefully, making them perfect antonyms. A frugal lifestyle would be the opposite of the minister's lavish lifestyle -> correct