Answer:
Neither Technician A or B
Explanation:
Both technicians are wrong. The diameter of bolt is not based on the top where wrench used, but on the smaller part below, it called shanks. Wrench size also not based on the top diameter but the width across the flat. The calculation for the length of a bolt also will not include the top/head, it only includes the shanks.
The correct answer is 19.72 °C. The first step is to determine the amount of heat that was lost per gram (30,000 J) / (390 g) = 76.92 J/g. Then to determine the temperature change, divide 76.92 J/g with the given specific heat of milk (76.92 J/g) / (3.9 J/g°C) = 19.72 °C.