Which is the correct option here?
Nuclide X has a half-life of 1 day and nuclide Y has a half-life of 5 days. In a particular sample, the activities of X and Y are found to be equal. When the activity is tested again after 10 days, the activity will be ________.
A. Entirely due to nuclide X. B. Due equally to nuclides X and Y. C. Mostly due to nuclide X. D. Mostly due to nuclide Y.