This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
Muscle acting both at knee and ankle joint is/are-a) Gastrocnemiusb) Soleusc) Plantarisd) Tibialis posteriore) Flexor hallucis longus 
Select and explain. 
A. a, B. bc, C. ac, D. b
C: ac
Answer: C: ac 
Explanation: Muscles acting on both hip and knee
-        Rectus femoris
-        Sartorius
-        Tensor fascia lata
Muscles acting on both knee and ankle
-        Gastrocnemius
-        Plantaris
Muscles acting on both ankle and toes
-        Extensor hallucis longus
-        Extensor digitorum longus
-        Flexor hallucis longus
-        Flexor digitorum longus