Solution

The correctly matched triplets are AFG, BEI and CDH. AFG: A ends with 'river' and F names the river, i.e. 'Thames'. Further, F ends with 'London's' and the use of apostrophe indicates possession which in turn indicates that it must be followed by a noun. Amongst, G, H and I, G mentions the noun phrase 'iconic landmarks'. BEI: B ends with the adjective 'entire' and must be followed by a noun that can be qualified by it. Between D and E, E must follow B, wherein the 'Milky Way galaxy' acts as the noun. E throws light on the proposition of the paper, i.e. the entire galaxy being located in a bubble. I adds more information to the same by stating that matter is less dense within this bubble. CDH: C talks about the 'giant-impact hypothesis' and H mentions a collision between Theia and earth. D connects these two phrases by mentioning how the moon was formed and giving additional information about Theia. Amongst these, only CDH is mentioned in the options. The other triplets in the options are incorrectly matched.