B1
describes something that could be avoided or that is not needed
Dictionary examples:
Tom brought an unnecessary umbrella to the desert, just in case it rained. (0.0)
Emma brought an unnecessary inflatable boat to her math exam. (0.0)
Sarah wore three unnecessary sweaters to the beach on a hot day. (0.0)
You don't want to make any unnecessary car trips in this weather. (33.8)
The aim is to kill the animal as quickly as possible without causing unnecessary suffering. (44.0)