Answer
${\bf 216}\, \text{MeV}$
Note: This is a rough estimate based on the graph, so your solution may vary slightly from ours.
Work Step by Step
The goal is to estimate the total energy released when a nucleus with a mass number of 240 fissions into two nuclei with a mass number of 120 each.
From the mentioned graph, the binding energy per nucleon for a nucleus with a mass number of 240 is about $ 7.6 \, \text{MeV} $.
So, the total binding energy $ B_{240} $ of the entire nucleus with mass number 240 is
$$
B_{240} = \text{Binding energy per nucleon} \times \text{Mass number} = (7.6 \, \text{MeV}) \times 240
$$
$$
B_{240} = \bf 1824 \, \rm {MeV}
$$
For a nucleus with a mass number of 120, the binding energy per nucleon, as estimated from the graph, is about $ 8.5 \, \text{MeV} $.
So, the total binding energy $ B_{120} $ for each nucleus with mass number 120 is:
$$
B_{120} = \text{Binding energy per nucleon} \times \text{Mass number}
$$
$$
B_{120} = (8.5 \, \text{MeV}) \times 120
$$
$$
B_{120} = \bf 1020 \, \rm {MeV}
$$
When the nucleus with mass number 240 splits into two nuclei with mass number 120, the total energy released is given by
$$
E_{\text{released}} =2B_{120}-B_{240}= 2(1020)-1824
$$
$$
E_{\text{released}} = \color{red}{\bf 216}\, \text{MeV}
$$
