Final answer:
Doug Jones would be most competent in residential property management due to his three years of focused experience in the residential sales and leasing sector.
Step-by-step explanation:
Doug Jones, having focused his work entirely in residential sales and leasing for the past three years, would most likely be most competent in residential property management. Given his experience in the residential sector, it correlates directly with the skills and knowledge required for managing residential properties, which includes dealing with tenants, overseeing property maintenance, and understanding residential market trends. While commercial leasing and land development might require some similar skills, there is a significant difference in market dynamics, and there would be a learning curve. Industrial property sales, being a different sector entirely, is the least related to his experience.