The answer is polygenic inheritance.
Many physical characters (traits) depend on many different factors, each of which is determined by different genes. This is called polygenic inheritance.
For example, the color of the skin in humans. The color of the skin results from the interactions of several factors determined by different pairs of genes:-Certain genes could affect the metabolism of skin melanocytes.-Other genes can determine the distribution of melanin in the thickness of the skin.-Some genes could determine the relative amounts of each of the two possible types of melanin.-Others may affect the production of certain hormones involved in the activity of melanocytes.
I'm pretty sure the answer is B
The rose family is a medium-sized family of flowering plants. The rose family (Rosaceae) is one of the major angiosperm families. The leaves are generally arranged spirally. Flowers of plants in the rose family are generally described as "showy". They are actinomorphic and almost always hermaphroditic. Rosaceae generally have five sepals, and five petals. They also have many spirally arranged stamens. The bases of the sepals, petals, and stamens are fused together to form a cup-like structure called a hypanthium. They can be arranged in racemes, spikes, or heads; solitary flowers are rare.