Answer:
D. a constant function divided by the sum of a constant function and an exponential function
Step-by-step explanation:
It's all about the meaning of the math symbols used to create the function. The exponential function is called that because the variable (t) is in the exponent of the expression.
The "numerator" is the part of the expression above the "divided by" line. The "denominator" is the part below that line. When describing a fraction like this, we say, "<the numerator> divided by <the denominator>."
The numerator is a number with no math symbols or variables: it is a constant. The same is true of the left term of the denominator.
The plus sign between the denominator terms indicate these terms are added together. The result of that addition is called a "sum." The terms either side of the plus symbol are those that the symbol is indicating the sum of.
So, we can describe the expression as ...
a constant function divided by the sum of a constant function and an exponential function
