Answer:
Option B, Barr graph
Step-by-step explanation:
A bar graph is used for comparing several items all together based on any certain parameter.
Here, the lead content is the comparison parameter while the six sample of contaminated water wells acts as different items being compared.
A line graph is good to show a continous varying data set, while a circle graph is good to represent the component constitution of any major substance and a data table is best to represent a data set with multiple attributes.
Hence, option B is correct