What special ingredient is found in a Primanti Bros. sandwich?

Here is the question :

WHAT SPECIAL INGREDIENT IS FOUND IN A PRIMANTI BROS. SANDWICH?

Here is the option for the question :

• Mozzarella sticks
• French fries
• Onion rings
• Jalapeño poppers

The Answer:

And, the answer for the the question is :

Explanation:

[STC0014857]. Primanti Bros. is a Pittsburgh institution famed for its French fry-stuffed sandwiches. The restaurant first opened in 1933, although the fries were not always a part of its identity. According to folklore, several years later, a customer arrived with a load of potatoes, which the chefs fried and added to sandwiches – a decision that was an instant success.