The proportion of patients who recovered from an infection disease was recorded as follows: 10% recovered in 12 days, 30% recovered in 18 days, 20% recovered in 24 days and 40% recovered in 30 days. What was the average days for recovery? Question 35 options: a) 14 days b) 23.4 days c) 21 days d) None of the options e) 5.85 days