Groupthink is a phenomenon in which a group's desire for unanimity and cohesion overrides critical thinking and objective decision-making. In a groupthink situation, members prioritize maintaining harmony and avoiding conflict over carefully evaluating different perspectives and potential risks. Dissenting opinions are suppressed or not expressed to preserve group cohesion, leading to a false sense of consensus. Groupthink can result in poor decision-making, as the group becomes insulated from external input and fails to consider alternative viewpoints or potential pitfalls. To counteract groupthink, it is important to encourage open and diverse discussions, welcome dissenting opinions, seek external evaluations, and promote critical thinking within the group.

Assertion: Groupthink is characterized by the appearance of consensus or unanimous agreement within a group.

Reasoning: Dissenting opinions are not expressed because individuals fear it result in group cohesion and make them unpopular. 

Assertion (A) is true but Reasoning (R) is not correct.

Groupthink is characterized by the appearance of consensus or unanimous agreement within a group. Members believe that everyone agrees on a particular decision or policy. Dissenting opinions are not expressed because individuals fear it would undermine group cohesion and make them unpopular. Studies have shown that such groups develop an inflated sense of control over events and tend to disregard or downplay external cues that suggest potential risks. In their pursuit of internal harmony and collective well-being, they become disconnected from reality.