What is a group?

a. collection of individuals who interact with each other, either towards a common goal or activity or to engage in relationships

b. the feeling of loss of identity, often experienced in a large group, that leads to deviant behavior

c. what we think and believe about ourselves and other people based on observations we make directly or learn about from other people

d. when the presence of others enhances performance on simple tasks but hurts performance on complex tasks ...