单选题 The picture was bought at a very low price, but it has turned out to be a(n) ______ painting.
A) invaluable B) invariable C) worthless D) valueless

【正确答案】 A

【答案解析】invaluable无价的，贵重的；invariable不变的，恒定的；worthless无价值的，无用的；valueless无价值的，无用的。