To determine the correct option, we need to consider the grammatical structure and punctuation of the sentence. Generally, when adding details or clarifications, a comma is typically used before "including."
The options you've provided are:
- M. expedition, including Henson,
- P. expedition, including Henson
- R. expedition including Henson,
- S. No change
The best choice would be to add a comma before "including" to clearly indicate that "Henson" is additional information relating to the "expedition."
Thus, the correct answer is M. expedition, including Henson,.