optional

Up to seven students are taught for two hours a day with the support of specialist teachers - and uniform is optional.

Sharing your contact information and the name of your insurance plan in the process is optional.

The government insists that the longer workday is optional, only affects the private sector, and can only be applied up to 37 days a year.

For this season, the cooling vests are optional, and some drivers, such as four-time world champion Max Verstappen, do not like them because they consider them uncomfortable and flawed.

"Drones are already redefining warfare. Having drone defences is no longer optional for anyone," Kallas said, referring to Russia's ongoing war in Ukraine and fears that Moscow may attack the EU.