I think that A is the correct answer.
C is awkward, wordy. "They" refers to geometrical symmetries so "they" could be eliminated to have a more concise sentence.
In option A, "their geometrical symmetries embellished with
old and new iconography and in a style
that varies from woman to woman and house to house" is an absolute phrase.http://grammar.about.com/od/ab/g/absoluteterm.htm
A group of words that modifies an independent clause as a whole.
An absolute is made up of a noun and its modifiers. It may precede, follow, or interrupt the main clause:
Their slender bodies sleek and black against the orange sky, the storks circled high above us.
The storks circled high above us, their slender bodies sleek and black against the orange sky.
The storks, their slender bodies sleek and black against the orange sky, circled high above us.