We can convert the ratio notation into a proportion.
x0.25=263.25
Cross multiply and solve for x:
0.25⋅26=3.25⋅x
We can solve this without using a calculator if we convert the decimals to fractions
41⋅26=341⋅x
41⋅26=413⋅x
Multiplying both sides by 4 allows us to get rid of the fractions on both sides.
26=13⋅x
x=2
We can test the answer choices. By inspection, x must be significantly larger than 0.25 since 26 is larger than 3.25. Testing 2 verifies the solution.
x0.25=263.25
20.25=263.25
41⋅21=341⋅261
81=413⋅261
81=81 ✓