Correct answer is:

a) 1,841,896 chocolates

Explanation

We know,
1 day = 24 hours
And, 1 week = 7 days
\therefore 1 week = \left(7\times24\right) hours
\rightarrow 168 hours.
Now,
Every 6 hours a chocolate factory produces = 65,782 chocolates
\therefore Every 1 hours a chocolate factory produces = \left(\frac{65,782}{6}\right) chocolates
\therefore Every 168 hours a chocolate factory produces = \left(\frac{65,782\times168}{6}\right) chocolates
\rightarrow 1,841,896 chocolates.
Ans: The end of a week a chocolate factory produces 1,841,896 chocolates.