Select the most appropriate option to fill in the blank.

Seeing my messy room, my mother taught me to keep everything in order. Now my room is _________.

spick and span

The most appropriate option to fill in the blank is spick and span.

The phrase "spick and span" means very clean and tidy. It is the most appropriate option in this context because it conveys the idea that the room is now very clean and organized, thanks to the mother's teachings.

The other options are incorrect.

• "On demand" means available immediately. It does not make sense to say that the room is on demand.
• "No avail" means to no purpose. It does not make sense to say that the room is no avail.
• "High and dry" means in a safe and secure position. It does not make sense to say that the room is high and dry.