The correct answer is B) Pintle. Pintle-type fuel injector nozzles are the least likely to experience carbon deposit buildup on the injection nozzle orifice. This is because the pintle design has a single central needle-like projection that opens and closes the nozzle, which allows for better fuel atomization and less carbon accumulation compared to other nozzle types. The other options are more prone to carbon buildup: A) Hole nozzles have a simple hole design that is more susceptible to deposits, C) Multi-pintle nozzles have multiple pins which can increase carbon formation, and D) Multi-hole nozzles also have a greater surface area for carbon to accumulate.