**Answer:**

To understand why option A is the correct answer, let's first understand the concept of parallel feeders and the purpose of directional relays.

**Parallel Feeders:**
Parallel feeders are multiple feeders that are connected in parallel to supply power to a common load. The purpose of parallel feeders is to distribute the load and ensure reliability in case one feeder fails.

**Directional Relays:**
Directional relays are protective devices used in power systems to detect faults and isolate faulty sections. They are designed to operate only when the fault current flows in a specific direction. This helps in protecting specific portions of the power system, such as feeders or transmission lines.

Now, let's analyze the options given:

**Option A: Non-directional relays at the source end and directional relays at the load end.**
This option is the correct answer because it ensures effective protection of parallel feeders. Here's why:

- Non-directional relays at the source end: Non-directional relays are used at the source end to provide overall protection for the parallel feeders. These relays can detect faults in any direction and operate to isolate the faulted section. Since parallel feeders are interconnected and share the load, it is important to have non-directional relays at the source end to ensure comprehensive protection.

- Directional relays at the load end: Directional relays are used at the load end to provide selective protection for individual feeders. By using directional relays, faults occurring in specific feeders can be detected and isolated, while the other feeders continue to supply power. This selective protection helps in minimizing power interruptions and ensuring continuous supply to the load.

**Option B: Non-directional relays at both ends.**
This option is not the correct answer because using non-directional relays at both ends does not provide selective protection for individual feeders. It means that any fault detected by the relays will result in tripping all the feeders, which is not desirable in parallel feeders.

**Option C: Directional relays at the source end and non-directional relays at the load end.**
This option is not the correct answer because it lacks selective protection. Having directional relays at the source end means that faults occurring in individual feeders may not be detected and isolated, leading to prolonged power interruptions and potential damage to the system.

**Option D: Directional relays at both ends.**
This option is not the correct answer because using directional relays at both ends does not provide comprehensive protection for parallel feeders. It may result in the failure to detect faults occurring in certain directions and therefore compromise the reliability of the system.

In conclusion, option A is the correct answer as it ensures comprehensive protection using non-directional relays at the source end and selective protection using directional relays at the load end.