Which is not a comparison operator in Splunk

A comparison operator is a symbol that compares two values and returns a Boolean result (true or false)2. Splunk supports various comparison operators such as <, >, =, !=, <=, >=, IN and LIKE2. However, ?= is not a valid comparison operator in Splunk and will cause a syntax error if used in a search string2. Therefore, option E is correct, while options A, B, C and D are incorrect because they are valid comparison operators in Splunk