B. It is better to have loved and lost than never to have loved at all.
Explanation:
Themes portray the central idea or thought of the narrator with an intended lesson for the audience to learn through the particular work of art. The first, third, and fourth option details an incident of being broken post-breakup. Thus, <em>only the fourth one suggests a thematic concern that involves every couple into it and displays the author's suggestion to them that it is more superior choice to be loved and lost as compared to being not loved at all as the author wishes them to be elated and cheerful at least for that time instead of living in dilemma whole life(to love or not).</em>
