The colon(:) is used to contain those fields which is calculated in the queries. In other words, the colon is used to insert the name for that field which is calculated then, the user uses the colon(:) and after that, he uses the expression in the columns or the field row. So, That's why the following option is true.
A spoofing attack. "<span>a situation in which one person or program successfully masquerades as another by falsifying data, thereby gaining an illegitimate advantage."</span>
