Final answer:
A person can travel to and from work in 9 different ways, taking into account the specific constraints of the one-way routes B and C.
Step-by-step explanation:
The question involves determining the number of ways a person can travel to and from work considering the constraints of one-way routes. To go to work, he can choose from three routes (A, B, and D) since C is one-way in the opposite direction. To return from work, he can choose from three routes (A, C, and D) since B is one-way and cannot be taken going home. Therefore, for each trip to work, there are three possibilities for the return trip, resulting in a total of 3 x 3 = 9 different combinations for traveling to and from work.