Select the most incorrect statement from the following statements:

a. gel cleaning is effective in cleaning food-packaging equipment.
b. centralized foam cleaning does not require the foam-charging operation.
c. a slurry is less fluid than foam and penetrates uneven surfaces more effectively.
d. lower pressure requires high flow rates at the nozzles to achieve the same impingement.
e. at high pressure of 40 to 55 kg/ cm², the nozzle flow rates can average approximately 5 l