Changing a fraction to its decimal form can be done by long division method. Dividing the denominator by its numerator will change the fraction into decimal form. Alternatively, you can use a calculator to do that for you. Below are the fractions with their decimal forms listed:
1.) 2/5 = 0.4 (D)
2.) 7/20 = 0.35 (A)
3.) 3/25 = 0.12 (C)
4.) 7/10 = 0.7 (B)