1. The problem asks for the median mark of 15 students based on the stem and leaf diagram. 2. The stem and leaf diagram represents the marks as follows: - 1 | 2 4 5 means 12, 14, 15 - 2 | 1 5 5 7 means 21, 25, 25, 27 - 3 | 0 2 2 6 9 means 30, 32, 32, 36, 39 - 4 | 2 3 8 means 42, 43, 48 3. List all marks in order: $$12, 14, 15, 21, 25, 25, 27, 30, 32, 32, 36, 39, 42, 43, 48$$ 4. Since there are 15 marks (an odd number), the median is the middle value, which is the $$\frac{15+1}{2} = 8^{th}$$ value. 5. Counting to the 8th value: 1: 12 2: 14 3: 15 4: 21 5: 25 6: 25 7: 27 8: 30 6. Therefore, the median mark is $30$. 7. Among the options given (A 21, B 27, C 30, D 32), the correct answer is C 30.