What type of business is a food truck?
No context provided
What form of business is a food truck?
small business
No context provided
What type of industry is a food truck?
restaurant and food
Food truck
https://en.wikipedia.org/wiki/Food%20truck
Food service (US English) or catering industry (British English) defines those businesses, institutions, and companies responsible for any meal prepared outside the home.[1] This industry includes restaurants, school and hospital cafeterias, catering operations, and many other formats
Foodservice
Food trucks are subject to the same range of concerns as other foodservice businesses.
Food truck
Small businesses are privately owned corporations, partnerships, or sole proprietorships which have fewer employees and/or less annual revenue than a regular-sized business or corporation
Small business
Small businesses in many countries include service or retail operations such as convenience stores, small grocery stores, bakeries or delicatessens, hairdressers or tradespeople (e.g., carpenters, electricians), restaurants, guest houses, photographers, very small-scale manufacturing, and Internet-related businesses such as web design and computer programming. 
Small business
Food trucks are part of the food service business. Food service defines those businesses, institutions and companies responsible for any meal prepared outside the home. This industry includes restaurants, food trucks, catering operations and many other formats. Food service businesses such as a bakery, delicatessen, restaurant and food truck are also considered small businesses. Small businesses are privately owned corporations, partnerships or sole proprietorships which have fewer employees and/or less annual revenue than a regular-sized business or corporation. 