Final answer:
Frito-Lay is executing a roll-out approach to market its new Doritos variety, starting with specific test markets and progressing to national distribution. Option b.
Step-by-step explanation:
Frito-Lay is using a roll-out approach (b) for its new variety of Doritos. This marketing strategy involves introducing the product in select markets initially and then expanding its availability progressively. The process typically starts with a test-market expansion in a few key cities or regions, before moving to the larger state-wide market, and neighboring states, and eventually escalating to mass commercialization at the national level.