AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
(B) Gold and platinum
Placer deposits occur in valley floors and hill bases, containing minerals not corroded by water. Gold, silver, tin, and platinum are the most important minerals found in placer deposits.
The passage directly states: "Certain minerals may occur as alluvial deposits in sands of valley floors and the base of hills. These deposits are called 'placer deposits' and generally contain minerals which are not corroded by water. Gold, silver, tin and platinum are most important among such minerals." The crossword clue (Down 1) also confirms "Found in placer deposit (4)" = Gold. Eliminate other options: Coal/mica → sedimentary/igneous rocks; Copper/zinc → veins and lodes; Gypsum/potash salt → evaporation (sedimentary).