Explanation:

In a mail merge operation, Word is usually the client. Let's understand why Word is considered the client in this scenario.

Mail Merge:
Mail merge is a feature in Microsoft Word that allows you to create personalized documents, such as letters, envelopes, labels, or emails, by merging a main document (template) with data from a data source. The data source can be an Excel spreadsheet, a database, or any other source that contains the required information.

Word as the Client:
In the mail merge operation, Word acts as the client, which means it is the application that initiates and controls the process. Here's why Word is considered the client:

1. Main Document:
- The main document is the template that contains the fixed content and formatting of the final merged document.
- Word is responsible for creating and managing the main document.
- It provides tools and options to design the main document according to the desired layout and format.

2. Data Source:
- The data source contains the variable data that will be merged into the main document.
- In this case, the data source is an Excel spreadsheet.
- Word acts as the client and connects to the Excel spreadsheet to retrieve the required data.

3. Merging Process:
- Word controls the merging process by using the data from the data source and inserting it into the appropriate placeholders (fields) in the main document.
- It retrieves the data from the Excel spreadsheet and populates the placeholders with the corresponding information.

4. Output:
- Once the merging process is complete, Word generates the final merged document.
- The merged document contains the personalized content from the data source merged with the fixed content from the main document.

Therefore, in the mail merge operation, Word acts as the client because it is the application that initiates and controls the process of merging the main document with the data source.