Confirmation bias "is caused by other people's ideas and opinions about a subject". (Answer D).
It is a common problem and occurs when a person seeks out evidence to support their preconceived opinions or views on a particular topic. This causes the 'bias' in the term 'confirmation bias' as the person is seeking to reinforce their preexisting view, rather than accept a more probable outcome. A classic example would be climate change skeptics seeking out source material that is anti-climate change in spite of overwhelming international consensus over the core aspects of climate change from the global scientific community. A person who seeks out and depends for their opinion on a very small component of the available evidence and chooses to ignore the mainstream literature is someone who has succumbed to confirmation bias.
