Normally the reports present conclusions are based on:

Impression
Investigation
Belief
Intuition

The correct answer is: B. Investigation

An investigation is a systematic inquiry to establish facts and reach a conclusion. It is a process of gathering and analyzing information to determine the truth about a particular situation. Investigations can be conducted by individuals, groups, or organizations. They can be formal or informal, and they can be conducted for a variety of purposes, such as to solve a crime, to determine the cause of an accident, or to investigate allegations of wrongdoing.

Impressions are subjective judgments that are formed without careful thought or consideration. They are often based on gut feelings or intuition, rather than on evidence or logic. Beliefs are convictions that are held to be true, even in the absence of evidence. They are often based on faith or personal experience, rather than on reason or logic. Intuition is the ability to understand something immediately, without the need for conscious reasoning. It is often described as a gut feeling or a sixth sense.

In the context of reports, conclusions are based on investigations. Investigations are conducted to gather evidence and information, which is then used to reach a conclusion. Impressions, beliefs, and intuition are not reliable sources of information, and they should not be used to draw conclusions in reports.