16) A

Total number of people tested = 50 + 50 + 200 + 150 = 450

Number of 5-17 years old females that could read the line = 28% of 50 = 14
Number of 5-17 years old males that could read the line = 32% of 50 = 16
Number of adult females that could read the line = 12% of 200 = 24
Number of adult males that could read the line = 18% of 150 = 27

Total number of people that could read the bottom line = 14 + 16 + 24 + 27 = 81

Percentage of people that could read the bottom line = (81 ÷ 450) x 100 = 18%