Mary knocks down 8 pins on the 1st delivery and scores a spare on the 2nd one ed knocks down 8 pins om the first delivery and 1 pin on the 2nd delivery a, 26,27 b, 25, 28 c, 27, 26 d, 28,25

To answer this, we would need to know the current score. However, this may help you figure it out. 

One can get a SPARE in bowling if they are able to knock down all the pins left in the second throw. In terms of the score, this means that the current score will be 10 plus the first throw in the next set. 

On the other hand, if you do not knock down all the pins in the second throw all you need to do is add the number of pins knocked down to your current score. 

Look at the attached picture to see a scenario:

C= syphilis would be the answer