In order to solve such questions it is necessary, that both the highlighted part are correct. If the first part is wrong we can directly reject the option choice without even reading the second one.

So, after reading the statement, I know that the first part is definitely not refuting any argument, it is merely a hypothesis. That is x happens conclusively y will also happen. We need a statement on similar lines.

20. In the argument given, the two highlighted portions play which of the following roles?

A) The first is an objection that the argument refutes; the second is the primary conclusion of the argument.-Not an objection- OUT
B) The first is a hypothesis that is used to support the position that the argument opposes; the second is a claim used to support the argument’s main conclusion.-OUT
C) The first is a hypothesis that, if true, would support the argument’s primary conclusion; the second is that primary conclusion.-Hold- The first part is correct and the second one is a conclusion- Correct
D) The first is a hypothesis that, if true, would support the argument’s primary conclusion; the second is a conclusion drawn to support that primary conclusion.- The second is the conclusion and not a statement supporting the conclusion- OUT
E) The first is an objection that the argument refutes; the second is the main conclusion of the argument- OUT


Hope this helps!