Before excavation begins, a contractor is required to determine the location of underground utility lines. The contractor should:

Explanation

Government Code section 4216.2 requires an excavator to contact the regional notification centre - USA North 811 in the north, DigAlert in the south - at least two working days and not more than 14 calendar days before beginning the excavation, and section 1541(b) requires the estimated location of utility installations to be determined before digging starts. Option (d) keeps the call and loses the notice period, which is the whole point: the member operators need those days to come out and mark. Option (b) inverts the system - the one-call centre exists precisely so that an excavator does not have to identify and contact every operator, and a letter to one utility leaves the rest unmarked. Option (c) leans on record drawings, which are routinely wrong about depth and alignment; once marks are down, section 4216.4 still requires hand tools or vacuum excavation within the tolerance zone.