Answer:
Illusion of invulnerability
Step-by-step explanation:
There are other symptoms of group think such as:
"an unquestioned belief in the morality of the group",
"the presence of “mind guards” who act as barriers to alternative or negative information".
However, the context shows that Illusion of invulnerability; that is a view one cannot be wrong explains the emergence of groupthink. This is evident from the fact that Leslie had convinced her group that there was no way that they could do poorly on the group project.