An experiment was carried out to determine how different types of sugar solution affect the growth rate of the bacteria Escherichia coli (E - Scottish Highers Biology - Question 14 - 2022

In this experiment, the independent variable is the condition that is manipulated to observe its effect on the dependent variable. Here, the different types of sugar solutions (glucose, lactose, and fructose) are being tested to see how they affect the growth rate of E. coli. Therefore, the correct answer is:

C. Type of sugar solution