‘Yellow cake’, an item of smuggling across borders is

Yellowcake is the common name for the concentrated uranium product obtained by milling uranium ore; chemically it is a form of uranium oxide. Uranium is a heavy radioactive mineral used as a nuclear fuel, and ores are processed to produce concentrates (yellowcake) that are typically handled under strict controls [1]. The illicit movement and smuggling of such nuclear or radioactive materials across borders is a documented international concern, addressed in literature on combating illicit trafficking in nuclear materials [2]. The identification of “uranium oxide” as the correct choice for “yellowcake” is also reflected in civil‑service exam material listing the same options, confirming option 3 as the correct answer [3].

Sources

1. [1] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 9: Distribution of World Natural Resources > uranium > p. 37
2. [2] https://www-pub.iaea.org/MTCD/Publications/PDF/pub1309_web.pdf
3. [3] https://catalystias.org.in/adminpanel/uploads/previous_year_question/17237911751715687827GS%20PAPAR-1%201995.pdf