Select the option that can be used as a one-word substitute for the given group of words.
A sudden and violent change or upheaval

Correct option is B

The correct one-word for the given group of words is (b) Turbulence.
Explanation: "Turbulence" refers to violent disturbance or disorder, particularly sudden and forceful changes. (Hindi meaning: उथल-पुथल / अशांति)
Example: The country experienced political turbulence after the sudden resignation of the Prime Minister.
Meanings of the given other options:
· (a) Tranquility: Peacefulness, calmness (शांति)
· (c) Serenity: The state of being calm and untroubled (शांतिपूर्ण स्थिति)
· (d) Equanimity: Mental calmness and evenness of temper (मन की शांति / संतुलन)