Cosmic rays are sources of ionizing radiation potentially dangerous to the human organism. To quantify the dose of radiation received, the sievert (Sv) is used, defined as the unit of energy received per unit of mass. Exposure to radiation from cosmic rays increases with altitude, which can represent a problem for aircraft crews. Recently, accurate measurements of ionizing radiation doses were performed for flights between Rio de Janeiro and Rome. The results have indicated that the average radiation dose received during the cruise phase (which generally represents 80\% of the total flight time) of this intercontinental route is $2 \mu\mathrm{Sv}/\mathrm{h}$. International civil aviation standards limit to 1000 hours per year the working time for crews operating on intercontinental flights. Consider that the ionizing radiation dose for a chest radiograph is estimated at $0.2 \mathrm{mSv}$.
How many chest radiographs does the dose of ionizing radiation to which a crew member operating on the Rio de Janeiro-Rome route is exposed over one year correspond to?
(A) 8
(B) 10
(C) 80
(D) [options cut off in source]