Vowels are “a,e,I,o,u”.
Consonants are the rest of the letters of the alphabet (e.g. b, c, y)
Ratios are comparisons of two or more amounts. For example if I have 2 eggs and 5 pens, the ration of eggs to pens would be 2:5. Ratios can also be simplified. An example could be if I had 10 eggs and 50 pens my first ratio would be 10:50. To simplify this you must find the highest common factor and divide BOTH of the numbers by it. In 10:50, you would get 1:5 when you divide both sides by 10.
So (a) has 1 vowel and 4 consonants. The ration would be 1:4.
(B) has 2 vowels and 4 consonants. The ration would be 2:4 which can be simplified to 1:2.
IMPORTANT: make sure to not swap the sides of the numbers. It should be vowels:consonants, not consonants:vowels.
Hope this helped.