The correct answer is - B. mutualistic.
The symbiotic relationship shown in this graph is most likely a mutualistic symbiotic relationship. In a mutualistic symbiotic relationship, the two species benefit from one another, in a way they collaborate for the well being of both of them. This leads to a situation where with the increase in numbers of one of the species, the other species also experiences increase in numbers, and if one of them has a decrease in numbers, it is very likely that the other species will experience the same.
In this graph we have exactly that kind of situation, one of the species experiences increase in numbers, and the other species follows the same pattern, which most likely means that a mutualistc symbiotic relationship exist between these two species.
