A. Must be of adequate size to avoid over flow B. Must flow under gravity ½ to ¾ full C. Must be laid at least 2 to 3 m deep to collect /water from the basements D. All the above
A. Both a and r is true and r is the correct explanation of a B. Both a and r is true but r is not a correct explanation of a C. A is true but r is false D. A is false but r is true