Final answer:
The technician should use chlorhexidine as it is an effective antiseptic for patients allergic to alcohol. Antiseptics are suitable for use on living tissues, and the effectiveness of disinfectants has historically been compared to phenol.
Step-by-step explanation:
If a phlebotomy technician is preparing to collect a blood specimen from a patient who is allergic to alcohol, the technician should use an antiseptic that does not contain alcohol. The correct choice is A. chlorhexidine, which is a widely used antiseptic for skin preparation before procedures when alcohol cannot be used. It is effective against a broad spectrum of microbes and less likely to cause skin irritation in patients with alcohol sensitivities.
In the case of choosing suitable substances for microbial control, the answer is B. antiseptic. Antiseptics are used on living tissues to prevent infection, while other options like disinfectants are typically used on non-living surfaces.
The effectiveness of chemical disinfectants is often compared to A. phenol, which has been historically used as a standard of comparison due to its significant antimicrobial properties.