Correct option is B
The correct option is
(b) For.
The preposition
"for" is used to indicate a period or duration of time. In this case, the children will go to their grandfather's place
for two weeks, meaning they will stay there for the duration of two weeks.
Corrected Sentence: The children will go to their grandfather's place for two weeks during the vacation.
Meanings of all the given options:
·
By: Refers to a specific point in time or means of doing something.
By (तक)। ·
For: Indicates a period or duration of time.
For (के लिए)। ·
Since: Refers to a point in time from which something started.
Since (से)। ·
From: Refers to the starting point of an action or event.
From (से)।