参考答案：D

解析：[分析]词义辨析 此句要表示的是：公司的CEO为了表达对John长期服务的感谢，送了他一个礼物；而 be confirmed by由……所证实；be recorded由……记录下来；appreciate表达感谢时，常用appreciate one's efforts/help，例：We appreciate your efforts for the development of the company．(我们感激你对公司发展所作的努力)；而此句John's service was appreciated by后应跟sb.，而不是a present；acknowledge公开表达对……的感谢，例：We wish to acknowledge the support of the university．(我们想对学校的支持表示感谢。)；本句用的是 John's service was acknowledged with a present…因此D为答案。