To speed the process of surveying, surveyors use brass metal plates to record important information. The benchmarks, as they are called, are used to save time so surveyors do not have measure the datum plane each time. Benchmarks refer to what standard of measurement? Feet above sea level

Feet Above Sea Level

Step-by-step explanation:

A benchmark is a term in Surveying and Geo informatics, that describes a point of reference established at a known elevation which serves as basis in which other elevation or topographical point can be measured.

Therefore, when determining the benchmark, it's height is calculated relative to the vertical datum of the area, typically mean sea level, which is then recorded in FEET ABOVE SEA LEVEL.

Hence, Benchmarks measurements refer to FEET ABOVE SEA LEVEL.

b, i believe, but not sure.

( - 4 , -7 )

all the lines must parallel  

step-by-step explanation:

coordinates of c = ( - 1 , 2 )

3 units left = ( -4 , 2 )

9 units down = ( - 4 , 11 )