Which is not used to reach a conclusion in a formal proof?

In mathematics especially in verifying certain statements regarding geometry, two column proofs are used. A two-column proof contains a table with a logical series of statements and reasons that reach a conclusion. It is commonly present in geometry. Two column proofs always have two columns: statements and reasons. The other choices don’t fit in the definition of two column proof.

In science, the four ways to incorporate proof into the research paper are:

1.    If the research you are investigating has been with other research paper before.

2.    There is an experimental proof that the evidence is true.

3.    The research published belongs to a reliable source.

4.    There are citations of the evidence that you are investigating

  or  

step-by-step explanation:

if the four friends split the cost, p, of the pizza evenly, then each friend pays one-fourth of the cost of the pizza.

the expression is   or