A tester is used to check the conduction of electricity through two liquids,labelled and . It is found that the bulb of the tester glows brightly for liquid while it glows very dimly for liquid . You would conclude that.（ ）
A. liquid is a better conductor than liquid .
B. liquid is a better conductor than liquid .
C. both liquids are equally conducting.
D. conducting properties of liquid cannot be compared in this manner.