Muscular strength
in case you didn't know the definition of muscular strength, you could use process of elimination. it's not muscular endurance because endurance is testing how long you can do something over a period of time, and the question is asking about all at once. it's not flexibility or body composition because neither are testing how much force your body can exert. that leaves muscular strength.
according to the HEALTH AND SAFTEY GUIDELINES employers provide training to employees about safe work practices. hope I helped!