The word "foment" means "to encourage", so we can conclude that to initiate a rebellion is necessary the "foment". For this reason, the words "foment" and "rebellion" establish a relationship represented as "foment: rebellion". To complete the diagram, we need to find two words that have a similar relationship.
In the same way that to initiate a rebellion it is necessary that this rebellion is fomented, to initiate a war soldiers are necessary. For this reason, the most appropriate pair of words to complete the diagram is "soldiers: war".
The other options do not establish the same kind of relationship that "foment: rebellion"
.
