Select the option that can be used as a one-word substitute for the given group of words.
A period of ten years

Correct option is B

The correct one-word substitute for the given group of words is (b) Decade.
· Explanation: A "decade" refers to a period of ten years (Hindi: दस वर्षों का समय)।
· Example: She worked in the company for over a decade before retiring.
Meanings of the Given Options:
· Option (a) Century: A period of 100 years (Hindi: सौ साल)।
· Option (c) Biennium: A period of two years (Hindi: दो साल)।
· Option (d) Lustrum: A period of five years (Hindi: पाँच साल)।