Which of the following is/are synthetic fibres?
Acrylic is a synthetic fibre resembling wool used to knit sweaters, socks and shawls.
Polystyrene is also a synthetic fibre used for making protective packaging such as packing peanuts and CD and DVD cases, containers such as clamshells, lids, bottles, trays, tumblers, disposable cutlery and in the making of models.
Therefore, options C and D both are correct.