Answer:
Sufres
Step-by-step explanation:
Since this sentence is addressing "you", we need to conjugate the verb in "tu" form. Sufres is the option is "tu" form. To check, use the process of elimination.
Sufre: El/ella/usted
Sufras: Doesn't apply- ends in "as" when "sufrir" is an -ir verb.
Sufren: Ellos/ellas/ustedes