HELP ASAP WILL MARK BRAINLIEST!!! PLEASEEEEEEE I NEED HELP

The diagram shows a thermometer used to measure temperature.

The area on the thermometer marked with the letter A is called the ________.

no options :(

HELP ASAP WILL MARK BRAINLIEST PLEASEEEEEEE I NEED HELP The diagram shows a thermometer used to measure temperature The area on the thermometer marked with the class=