Answer:
The correct answer will be- anterior cruciate ligament (ACL), medial collateral ligament (MCL), and meniscus.
Step-by-step explanation:
An unhappy triad is a form of injury caused by the rupture of the three important anatomical structure in the knee joints that is medial collateral ligament, anterior cruciate ligament and the meniscus.
The common cause of this injury is the lateral force exerted by the upper body on the knee while keeping the foot fixed on the ground.
Since this injury affects the knee, therefore, is also known as the blown knee.
Thus, medial collateral ligament, anterior cruciate ligament and the meniscus is the correct answer.