The consumer product most significant in terms of radiation exposure is:

Cigarettes are significant in terms of radiation exposure due to the presence of polonium-210, a radioactive substance that naturally occurs in tobacco plants. When tobacco is burned, polonium-210 is released and can be inhaled by the smoker. This radioactive material contributes to the overall radiation dose received by smokers and those exposed to secondhand smoke.

In contrast, while wrist watch dials, TV receivers, and microwave ovens can emit low-level radiation, their contributions to overall radiation exposure are minimal compared to the exposure from smoking cigarettes. Wrist watch dials might contain radium or other radioactive materials, but the levels are typically quite low. TV receivers emit very low levels of radiation that are well within safety standards. Microwave ovens, when functioning properly, do not pose a significant radiation risk to consumers.

Thus, cigarettes stand out as the consumer product that exposes individuals to a more substantial and concerning level of radiation compared to the others listed.