It would have to be letter D my guy, if you know what centuries and decades are this is easy
Answer:

Variable is a symbol that represents a quantity in a mathematical expression, as used in many sciences. Variable (research), a logical set of attributes. Variable star, a type of astronomical star.

A constant, sometimes also called a "mathematical constant," is any well-defined real number which is significantly interesting in some way. A function, equation, etc., is said to "be constant" (or be a constant function) if it always assumes the same value independent of how its parameters are varied.
4, 5, and 7 are mutually coprime, so you can use the Chinese remainder theorem right away.
We construct a number
such that taking it mod 4, 5, and 7 leaves the desired remainders:

- Taken mod 4, the last two terms vanish and we have

so we multiply the first term by 3.
- Taken mod 5, the first and last terms vanish and we have

so we multiply the second term by 2.
- Taken mod 7, the first two terms vanish and we have

so we multiply the last term by 7.
Now,

By the CRT, the system of congruences has a general solution

or all integers
,
, the least (and positive) of which is 27.