Final answer:
b) The valve core should be removed to completely deflate a truck tire.
Step-by-step explanation:
The correct method to completely deflate a truck tire is to remove the valve core. When the valve core is removed, it allows the air inside the tire to escape quickly and completely.
Depressing the valve pin may release some of the air but it will not completely deflate the tire. A hydraulic bead buster is used to separate the tire bead from the rim for tire changing purposes, not deflating the tire.
Separating the split rim is also not the appropriate method for deflating the tire. Split rims are used in heavy-duty truck tires, and separating them is a dangerous process that should only be performed by trained professionals.