Mark the letter A, B, C or D on your answer sheet to indicate the word or phrase that is OPPOSITE in meaning to the underlined and bold part in the following question.
Although Valentine's Day has become a global industry with more than 80 million roses sold worldwide, the origins of the day are unclear and hidden in the mists of time.
A.traced back to the ancient people
B.a long time ago and unforgettable
C.new enough for anyone to confirm
D.still a mystery to everybody