In the given expression, the decaying factor is (0.9333)^t:

Due to that factor, for each unit t increases, the expression is reduced to 0.9333 of the previous value. The relative difference between the previous value and the next one, is:

Then, this equation models a decay of 6.67% per unit t. It could be a radioactive decay rate where the time is measured in years.
Therefore, the correct choice is: Option A) A radioactive decay of 6.67% per year.