According to federal regulations, piping and piping components in a hydraulic system must be designed with a burst pressure of not less than how many times the system's maximum operating pressure?

Why C is correct

46 CFR §28.405(b) and §28.880(b) both specify that piping and piping components must be designed with a burst pressure of not less than four times the system maximum operating pressure. Two, three, and six times are plausible safety factors used in other contexts but are not the regulatory requirement for hydraulic piping.