Final answer:
The statement is false; while a high longitudinal balance is good for resisting interference, it is not considered a minimum requirement for the performance of DSL circuits.
Step-by-step explanation:
The statement that an optimum DSL circuit needs to have greater than 60Db longitudinal balance is false. Longitudinal balance is a measure of the balance of a signal's power between the two wires in a twisted pair. It is related to how resistant the line is to interference from external sources and crosstalk between lines. A longitudinal balance of 60 dB is high, but DSL specifications do not generally consider that a minimum requirement; other factors are usually more important for the overall performance of DSL circuits.