Final answer:
The expression -5yf^2 contains a coefficient and two variables: y and f^2.
Step-by-step explanation:
The expression -5yf^2 contains a coefficient and two variables. The coefficient is -5, which is the number that multiplies the variables.
The variables are y and f^2, where y represents one variable and f^2 represents another variable raised to the power of 2.
So, the correct answer is option a) -5, y, f^2.