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.
I would advise her not to lose any weight at all as according to the skin fold test which measures her body mass index she has 22 percent body fat which is in the normal/healthy weight range. Any BMI between 18.5 to 24.9 is considered healthy. If she really wanted to she could lose the 7 pounds as long as she stays within the healthy BMI levels and doesn't drop any lower than 18.5 but she really doesn't need to.