The options that combine in a correct way the first three sentences of the passage are:
When I was visiting New York, I saw Amir, who lives there.
I saw Amir when I was visiting New York, which is where he lives.
I saw Amir, who lives in New York, when I was visiting.
The first of these sentences adds variety to the passage and correctly combines the three sentences by building the sentence with a subordinate clause ("When I was visiting New York"), an independent clause ("I saw Amir") and a non-defining relative clause ("who lives there"). The second and third sentences also include these three types of clauses (a subordinate clause, an independent clause and a relative clause). Moreover, in the three sentences, the subordinate clause is introduced by the subordinating conjunction "when".
