Which skill is NOT essential in business and financial operations occupations?

a good public speaking voice

basic mathematical competency

computer and information processing skills

problem-solving ability

The question is asking us ""Which skill is NOT essential in business and financial operations occupations?" Let's imagine someone working in business - they could for example work in an office, in front of computer, analysing the finances of their company. They would not necessarily be talking to the clients directly or presenting the company to the public - so the correct answer is "a good public speaking voice"