Which of the following is a common topping available for Jersey Mike's subs?

Lettuce is a common topping available for Jersey Mike's subs, as it is a standard ingredient for many sandwich shops. It adds freshness and a crunchiness to the subs and complements a variety of meats and cheeses. Lettuce is widely recognized as a staple in sandwich preparation, often included alongside other toppings like tomatoes, onions, and sauces to enhance flavor and texture.

The other options provided, such as sauerkraut, pineapple, and guacamole, are not typically featured as standard toppings at Jersey Mike's. Sauerkraut is usually associated with specific types of ethnic cuisine, while pineapple tends to be more of a niche option, often used in specific sandwiches or burgers rather than as a common subs topping. Guacamole can be popular in some settings but is not a mainstay topping on Jersey Mike's menu, which focuses more on classic sub ingredients.