As a result of（ ） — one of the sources of synonyms, gain the upp

As a result of（ ） — one of the sources of synonyms, gain the upper hand becomes the synonym of win.
A、borrowing
B、dialects and regional English
C、figurative and euphemistic use of words
D、coincidence with idiomatic expressions
【正确答案】：D
【题目解析】：同义词的来源有四种，题中考察的是与习语的巧合。gain the upper hand是一句习语，表示“赢；占上风”。