The image doesn't display so we can't see the fraction.
First work out 55-25=30.
So we now apply the fraction to 30. For example if the fraction is ¼, then it's ¼ of 30=30/4=7.5.
We then add this to 25 (the start): 25+7.5=32.5 is a quarter of the way between 25 and 55 (answer b).
Answer a can't be correct because it isn't between 25 and 55.
¾ of 30=90/4=22.5; 25+22.5=47.5 is three quarters the way between 25 and 55, so since 47.5 is not listed, the fraction wasn't ¾.
41.5-25=16.5 and 16.5/30=11/20, so the fraction would be 11/20 if the answer was 41.5 (c).
34-25=9 and 9/30=3/10 or 0.3, so the fraction would be 3/10 or 0.3 if the answer was 34 (d).
I think the fraction was ¼ and the answer is b.