Why is it invalid to have a fraction with denominator equal to zero (for example, a/0)?

• A. Because the numerator must always be larger than the denominator
• B. Because if the denominator were zero, you could still represent the parts visually by creating zero slices of a circle
• C. Because zero is not a natural number and fractions only allow natural-number denominators
• D. Because division by zero is undefined, so a/0 has no meaning in arithmetic

Answer: (D)