Explanation:

Excel uniquely identifies cells within a worksheet using column letters and row numbers. Here's a detailed explanation of each option:

a) Cell names:
Excel allows users to assign custom names to cells, known as cell names. However, these names are not used to uniquely identify cells within a worksheet. Cell names are typically used for easier referencing and formula calculations.

b) Column numbers and row letters:
In Excel, columns are labeled with letters from A to Z, and then from AA to ZZ, and so on. Rows are labeled with numbers starting from 1. While column numbers and row letters are used to reference specific cells, they do not uniquely identify cells within a worksheet. For example, there can be multiple cells with the same column number and row letter combination (e.g., A1, A2, A3, etc.).

c) Column letters and row numbers:
This is the correct option. Excel uniquely identifies cells within a worksheet using a combination of column letters and row numbers. Each cell is referenced by specifying the column letter followed by the row number. For example, A1 refers to the cell in column A and row 1, B2 refers to the cell in column B and row 2, and so on. This method of identification ensures that each cell has a unique address within the worksheet.

d) Cell locator coordinates:
This option is not accurate. "Cell locator coordinates" is not a commonly used term in Excel. While the term "coordinates" may refer to the combination of column letters and row numbers used to identify cells, the term "cell locator coordinates" is not commonly used in Excel terminology.

In summary, Excel uniquely identifies cells within a worksheet using column letters and row numbers. This method ensures that each cell has a unique address within the worksheet, allowing users to easily reference and work with specific cells.