Select the most appropriate word to fill in the blank.
Carbohydrates are so called because they _____ carbon, oxygen and hydrogen.

Correct option is A

The correct option to fill in the blank is (a) contain.
Contain: To have or hold something within (अंदर रखना, समाहित करना)
Example: This fruit contains a lot of vitamin C.
Other options:
· (b) Cover – To place something over or around (ढकना)
· (c) Consist – Always used with "of" (e.g. consists of...) (से मिलकर बनना)
· (d) Codify – To arrange laws or rules systematically (संहिताबद्ध करना)