Explanation:

- The original sentence, "then Neha came on to meet him," is awkward and needs improvement for clarity and correctness.

- Option 1: "when Neha was coming to" implies an ongoing action and does not fit well with the simple past tense action "was going." This creates a tense mismatch.

- Option 2: "before Neha was coming to" suggests that Abhishek was already going to the church before an unfinished action, which is less likely in this context.

- Option 3: "when Neha came to" is clear and grammatically correct. It indicates that Neha arrived at the same time or just after Abhishek started going.

- Option 4: "no improvement" is incorrect because the original phrase is awkward.