单选题 The manager in charge of advertising plans to return the promotional pens he ordered because the company logo on them was not ______ enough.
【正确答案】 A
【答案解析】[解析] 词汇：形容词
1．这是一道词汇题，选项均为形容词。
2．形容词certain经常用于事实确定。字迹和图像清晰必须使用distinct。