An 18-year-old football player is seen in the emergency ward with severe knee pain incurred after being hit by a tackler while running. Which of the followingfindings on physical examination is most sensitive for an anterior cruciate ligament injury?a. Excessive valgus laxity of the kneeb. Excessive varus laxity of the kneec. Locked kneed. Positive Lachman teste. Positive posterior drawer test