Final answer:
To reduce static and soften hair in a dry climate, surface conditioning is the recommended approach. It involves the use of products that coat and moisturize the hair, akin to fabric softeners, and is less damaging than chemical treatments.
Step-by-step explanation:
To reduce static and soften the hair fiber in a dry climate, the best approach would be b) surface conditioning. This involves the use of products that coat the hair shaft and reduce static electricity. Similar to how fabric softeners work by coating the surface with electrically charged compounds that neutralize the charge on fibers and impart lubricity, surface conditioners add moisture and reduce the friction between hair strands, leading to less static and softer hair. Unlike chemical treatments like perms or hair relaxing, which involve breaking and reforming the hair's disulfide bonds requiring harsh chemicals, surface conditioning is much gentler on the hair.
Static electricity is common in dry climates and is more problematic when the air is less humid. To validate this, you could perform an easy experiment as illustrated by Take-Home Experiment: Electrostatics and Humidity, where rubbing a comb through your hair in a dry versus a moist environment (like a bathroom post-shower) shows how static effects are more pronounced in dry conditions.