Final answer:
The recommended position for preventing hip flexion contractures is prone (lying face down with upper limbs and lower limbs touching at the sides) for at least 30 minutes, 3-4 hours a day.
Step-by-step explanation:
The position recommended for preventing hip flexion contractures is b) Prone (30 min at least 3-4 hours a day). This position involves lying face down with the upper limbs and lower limbs touching at the sides. By spending time in this position, it helps to stretch and strengthen the muscles that flex the hip joint, preventing contractures.