Final answer:
c) Cirrus SR20. The Cirrus SR20 is the aircraft characterized by either having more windows or a v-tail.
Step-by-step explanation:
The aircraft characterized by either having more windows or a v-tail is the Cirrus SR20. The Cirrus SR20 has large windows along the sides, providing better visibility to the pilot. Additionally, it features a distinctive V-shaped tail, also known as a v-tail, which consists of two surfaces positioned in a V-shape instead of the traditional horizontal and vertical tail surfaces.