Step 1: Understanding the Concept:
Occupational ergonomics and biomechanics study Cumulative Trauma Disorders (CTDs) and Repetitive Strain Injuries (RSIs) arising from repetitive manual tasks.
Step 2: Detailed Explanation:
Repetitive Strain Injury (RSI) (such as Carpal Tunnel Syndrome, Tenosynovitis, and De Quervain's disease) is a work-related musculoskeletal disorder caused by repetitive mechanical motions, forceful exertions, and awkward postures that cause micro-trauma and inflammation primarily in the tendons, tendon sheaths, and peripheral nerves of the hand, wrist, and forearm.
Step 3: Final Answer:
Therefore, RSI relates to disorders affecting mainly the Hand, wrist and forearm, matching option (B).