To find the current population of elk at the park, we need to evaluate the function \( f(x) = 1200(0.8)^x \) when \( x = 0 \) (which represents the current year).
Calculating \( f(0) \):
\[ f(0) = 1200(0.8)^0 \]
Since \( (0.8)^0 = 1 \), we have:
\[ f(0) = 1200 \times 1 = 1200 \]
Thus, the current population of elk in the park is 1200.
The answer is C. 1200.