An array is a type of data structure that stores multiple values of the same data type in a fixed-size sequence. An array would be the best option for a developer to use when storing the months of a year and when performance is a key consideration because an array allows fast access to any element by using its index number. A vector, a list, and a string are not types of data structures that offer fast access to elements or store multiple values of the same data type in a fixed-size sequence. Reference: CompTIA IT Fundamentals+ Study Guide: Exam FC0-U61, Second Edition, Chapter 4: Programming Concepts and Data Structures, page 147.