Choose the idiom/phrase that can substitute the highlighted group of words meaningfully.
The automobile industry is the source of livelihood of many people of Manesar.

The correct answer is (b) Bread and butter.
Explanation:
"Bread and butter" is an idiom that refers to the main source of income or livelihood. In this context, it describes the automobile industry as the primary source of income for the people of Manesar.
Meanings of all options:
· In the same boat: In the same situation.
· Bread and butter: A source of income.
· Through thick and thin: Through good times and bad times.
· Go down the drain: To be wasted or lost.
Correct sentence:
"The automobile industry is the bread and butter of many people of Manesar."