Concept:The median is the middle value when the total number of observations is considered.Explanation:Total frequency is 1+2+7+5+4+3=22.Since there are 22 values, the median is the average of the 11th and 12th values.Cumulative frequencies: 0:1, 1:3, 2:10, 3:15.The 11th and 12th values both fall in mark 3.So the median mark is 3.Answer:3