Concept: Rounding a number to two decimal places means keeping only two digits after the decimal point.Explanation:The given number is 5178.3426.Identify the hundredth digit, which is the second digit after the decimal: 4.Look at the next digit, the thousandth digit: 2.Since 2<5, we do not increase the hundredth digit.Therefore, 5178.3426 rounded to two decimal places is 5178.34.Answer:5178.34Correct option: C. 5178.34