I’ve had a talk with the guy who got the question sheet, it is definitely “14 k_ of g_ in a f_ p_ d_” so the ‘a’ is the word ‘a’ and not the first letter of a missing word.
He can’t find out the answer at present because whoever can answer all the riddles on the sheet wins a prize, so the person who knows the answer ain’t tellin’!!
Looking at the rest of the questions on the sheet it could quite easily have been lifted from the internet as I recognised them all from internet examples, except this one of course. So, having said that, there is always the chance that the company have made this one up either thinking they are clever or purposely sabotaging the quiz to stop anyone winning the prize. For what it’s worth the company is question is called “Auto Trader” which is a magazine where people and businesses advertise second hand cars for sale so it might be worth looking down the auto route in search of an answer, but I still got nuthin’.
I will keep pestering him so he doesn’t forget to find out the answer when the “prize-time” has ended.