Final answer:
A 23 G needle is the correct choice for administering an intradermal (ID) injection, as it is thin enough to minimize discomfort and is appropriately sized for the depth required.
Step-by-step explanation:
The correct needle gauge for administering an intradermal (ID) injection would be option b) 23 G. Intradermal injections require a small, fine needle because the injection is made just below the surface of the skin into the dermal layer of the skin. A 23 gauge needle is typically used because it is thin enough to cause minimal discomfort and is of appropriate length for the depth of an ID injection. Using a larger gauge, such as 18 G or 14 G, would be inappropriate because they are too large and would cause unnecessary trauma to the skin. A 30 G needle could potentially be used, but it is generally reserved for subcutaneous injections due to its shorter length and finer gauge.