The correct option is A b,c,a,d
Since three of the sentences start with a pronoun, and one with a noun, the one starting with a noun should come first, followed by a subordinate clause introduced by a subordinate conjunction, then a query about the previous sentence, followed by its explanation. Therefore, the order "b,c,a,d" or Option C, that is, "My friend selected everything he needed very quickly. But his selections were fantastic. How could he choose things so quickly? He has been in marketing job for many years." is correct. The rest of the options do not adhere to the goal, hence incorrect.