Question

the sight of marco standing in the ice garden is one she has imagined so many times before while alone in the icy expanse of flowers, it does not seem real despite the darkness of his suit against a bower of pale roses.
source: the night circus
in this sentence, bower means:
a framework that supports climbing plants
a small roofed building affording shade and rest
a low woody plant usually having several stems
an arrangement of flowers that is usually given as a present

Explanation:

In the context, "bower" is described as something against which Marco's dark - suited figure is set, with pale roses. A bower often refers to a framework that supports climbing plants. The description suggests a structure with roses around it, which aligns with the idea of a framework for climbing plants.

Answer:

A. a framework that supports climbing plants