33. Which of the following best describes mathematical expressions and equations? A. A mathematical expression is a phrase that consists of variables or constants, or combinations of numerical and literal coefficients while a mathematical equation expresses the equality of two mathematical expressions at its right and left side. B. A mathematical equation is a phrase that consists of variables or constants, or combinations of numerical and literal coefficients while a mathematical expression expresses the equality of two mathematical expressions at its right and left side C. A mathematical expression is a phrase that does not consists of variables or constants, or combinations of numerical and literal coefficients while a mathematical equation expresses the equality of two mathematical expressions at its right and left side. D. A mathematical expression is a phrase that consists of variables or constants, or combinations of numerical and literal coefficients while a mathematical equation expresses the inequality of two mathematical expressions at its right and left side.