The correct answer is: B. he hurt himself.
However, since "Susana" is a female name, the correct pronoun should be "she." The sentence should actually read: "Susana had an accident and she hurt herself." Since "she" is not an option, if we strictly choose from the options and correct for gender, B is the closest, but none of the options perfectly fit without changing the pronoun.
If the options were meant to follow Susana's act of hurting her own arm, none of the choices listed are correct without being adjusted.