Tony is four years younger than his brother Josh, and two years older than his sister Cindy. Tony also has a twin brother, Evan. All the ages of the children totaled together is 66. How old is Tony?

Let Tony's age be $T$.
Let Josh's age be $J$.
Let Cindy's age be $C$.
Let Evan's age be $E$.

• "Tony is four years younger than his brother Josh":

• "Tony is two years older than his sister Cindy":

• "Tony also has a twin brother, Evan":

• "All the ages of the children totaled together is 66":

Combine the $T$ terms:

Combine the constant terms:

Subtract 2 from both sides:

Divide by 4:

Tony's age is 16. Comparing this to the given options:
A. 14
B. 20
C. 16
D. 22
Option C matches our calculated age.

The final answer is $\boxed{\text{C. 16}}$