Which of the following is a metal?

Q. Which of the following substances are elements ?
Water, Salt, Mercury, Iron, Marble, Diamond, Wood, Nitrogen, Air, Graphite, Hydrogen, Oxygen, Sugar, Chlorine

Q. Which of the following groups of materials contains only metals?
(a) copper, iron, plastic, glass
(b) copper, gold, iron, silver
(c) cotton, iron, wood, gold
(d) glass, wood, cotton, air

Q. Which of the following are 'pure substances' ?
Ice, Milk, Iron, Hydrochloric acid, Calcium oxide, Mercury, Brick, Wood, Air