Question

read the excerpt from the dark game. but how would hall get that telegram? that would take some doing, he admitted. then hall remembered mr. h., one of his trusted operatives. it was mr. h. who had alerted m18 to the suspicious activities of swedens chargé daffaires in mexico city, folke cronholm. sharp - eyed mr. h. had noticed that cronholm was making frequent visits to the telegraph office, far more visits than one would expect from a representative of the swedish government, given the limited relationship between that government and mexico. which inference can a reader make based on the information in the excerpt? folke cronholm was spying for the allied nations. folke cronholm was a german diplomat. folke cronholm was secretly working for the germans. folke cronholm was receiving many personal telegraphs.

Explanation:

Mr. H. is an operative of MI8 (British intelligence). He noticed Cronholm's suspicious visits to the telegraph - office. Since MI8 is part of the Allied intelligence (assuming the context of World War - related intelligence work as in "The Dark Game" which often deals with WWI/WWII - era espionage), and Mr. H. is alerting MI8 about Cronholm, it can be inferred that Cronholm is a threat to the Allied cause. Spying for the Germans (who were the main enemy of the Allies in WWI and WWII) would make his frequent telegraph - office visits (possibly sending or receiving messages for the German war effort) a suspicious activity.
There is no indication that he is a German diplomat (he is Sweden's chargé d'affaires). There is no mention of personal telegraphs. And if he were spying for the Allied nations, Mr. H. (an Allied operative) would not be alerting MI8 about his activities.

Answer:

Folke Cronholm was secretly working for the Germans.