Environmental factors were considered for their influence on the growth of certain bacteria. An E. coli bacterial colony was placed in each of three petri dishes containing the same nutrient concentrations. The pH level of each nutrient concentration was varied according to Table 1. After 6 hours, the percent growth of E. coli bacteria was recorded. Table 1

Dish pH Level Percent Growth
1 6 34
2 7 84
3 8 26
According to Table 1, what might best contribute to the growth of E. coli bacteria?
Group of answer choices
a pH level above 7
b pH level above 8
c pH level near 7
d pH level below 6