At Sreeman’s fast food, $\frac{5}{8}$ of the orders included Dhoklas. 
At Haldiram’s,  $\frac{9}{13}$Of the orders included Dhokla. 
At Swadish Kitchen, $\frac{7}{9}$ of the orders included Dhoklas. 
At which restaurant did Dhoklas make up a greater fraction of the food sold?

To compare all these values, we have to have a GCF ( greatest common factor) as the denominator to figure out the solution, 

The GCF of this is 936 

Sreeman’s fast food=  $\frac{585}{936}$

Haldiram=  $\frac{648}{936}$

Swadish Kitchen=  $\frac{728}{936}$

So, we can see that Swadish Kitchen sold the most Dhokla’s out of these three restaurants.

Hence, option C is the correct answer.