Final answer:
Without the specific work shown, we cannot accurately determine the error; however, the sum of 18 + 30 is 48. An error in calculation is the most probable issue since factoring and distributing are not typically involved in a simple addition problem.
Step-by-step explanation:
The student was asked to describe the error in the work shown for finding an expression equivalent to the sum of 18 + 30. Without the work being provided, it's challenging to identify the exact error. However, the possible answers point to common mistakes in mathematics, such as finding factors, distributing a number incorrectly, or miscalculating a sum.
In the context of the question, if we consider the sum 18 + 30, the correct result would simply be 48. There should be no need for factoring or distributing, as this is a straightforward addition problem. Therefore, if an error has been made, it most likely relates to the calculation of the sum itself (option c).
For this specific problem, no work is shown to point to an error in distributing a number (such as 6, mentioned in one of the options), and there is no context provided that would require finding factors. Thus, based on the information provided, the likely error would be in calculating the sum incorrectly.