Which of the following plants belongs to the genus Viola?

The plant that belongs to the genus Viola is indeed Viola. This genus includes various species commonly known as violets and pansies. They are characterized by their distinctively shaped flowers and can range in color from purple to yellow and white. Understanding plant taxonomy is essential in horticulture, as it helps identify and classify plants based on shared characteristics.

The other choices represent different genera: Zinnia belongs to the genus Zinnia, Daisy to the genus Bellis or Aster, and Lavender belongs to the genus Lavandula. Each of these plants has its unique features and cultural requirements, which further emphasizes the importance of correctly identifying plants within their respective genera in horticultural practice.