What characterizes a synchronous call in programming?

A synchronous call in programming is characterized by the fact that the sender is blocked and must wait for the receiver to process the request and send back a response. This means the control is temporarily handed over to the receiver until the operation is completed and a return message is received. During this time, the sender cannot proceed to execute subsequent tasks as it awaits the completion of the current operation. This behavior is a fundamental aspect of synchronous communication, where the interaction occurs in a sequential manner and emphasizes a direct correlation between the call and the response.

In contrast, other options describe different behaviors that are not applicable to synchronous calls. For instance, if a sender could perform other tasks while waiting for a response, it would indicate an asynchronous model where the sender continues operating without being blocked. The mention of automatically asynchronous processes does not align with the synchronous operation, as it suggests a model where tasks can occur independently. Lastly, the idea of multiple receivers responding simultaneously is also unrelated to synchronous communications, which focus on a singular interaction between a sender and a receiver at any given time.