The natural soluble impurities are removed from the fibres by a special operation called

Correct option is C

Scouring is the process used to remove natural soluble impurities, such as waxes, proteins, and pectins, from fibers like cotton, wool, or silk. Scouring is typically done using an alkaline solution, which helps to remove these impurities and prepare the fibers for further processing, such as dyeing or finishing.
Information Booster: Scouring is a critical first step in the textile industry to clean fibers before they undergo further treatments such as dyeing and bleaching. It removes the natural impurities like grease and pectin that can affect the appearance and quality of the final product. After scouring, the fibers are cleaner, more absorbent, and ready for additional treatments.
Additional Knowledge on Incorrect Options:
· Desizing (Option A): Desizing is the process of removing the size or starch applied to fibers during weaving. It is typically used for woven fabrics to remove starch, not the natural soluble impurities found in fibers like cotton and wool.
· Bleaching (Option B): Bleaching is used to remove color or whiten fibers, but it does not specifically target natural soluble impurities.
· More than one of the above (Option D): This is incorrect because scouring is the primary method for removing natural soluble impurities from fibers.
· None of the above (Option E): This is incorrect, as scouring is the correct answer.