Final answer:
Without specific data on the actual radioactivity of the materials and local environmental radiation levels in Dallas and Denver, it is not possible to accurately calculate the change in annual radiation dose due to the family's move. The correct answer is D) Not enough information.
Step-by-step explanation:
The question of whether a family moving from a wood-frame home in Dallas to a brick home in Denver will experience a change in their annual radiation dose has to do with the differences in building materials and location. However, there is not enough information provided to determine the exact change in mrems. Factors such as altitude, natural radioactivity of the building materials, and the cosmic ray exposure would need to be considered. In general, higher altitude cities like Denver are associated with increased exposure to cosmic rays compared to lower altitude cities like Dallas. Brick could potentially have higher natural radioactivity than wood, but without specific data on the actual radioactivity of the materials and local environment in Dallas and Denver, one cannot accurately calculate the change in annual radiation exposure.