The researcher painstakingly recorded his observations, he then analyzed the data, and finally he published his finding…

The researcher painstakingly recorded his observations, he then analyzed the data, and finally he published his findings.

1. A.The researcher painstakingly recorded his observations, he then analyzed the data, and finally he published his findings.
2. B.The researcher painstakingly recorded his observations, analyzed the data, and published his findings.
3. C.The researcher painstakingly recorded his observations; analyzed the data; and published his findings.
4. D.The researcher painstakingly recorded his observations, then he analyzed the data, and finally he published his findings.