Answer:
A melodrama is a dramatic or literary work where the plot is sensational.
The correct answer is the first option.
The sentence that presents the correct subject-verb agreement is the first one since in it we are talking about "heavy rains" OR "fast-melting snow". In other words, the subject is coordinated by the conjunction "OR" which makes the subject singular. The verb "causes" is conjugated in the third person singular.
