Explanation:

- (a) Scarcely had: This part is correct. "Scarcely had" is commonly used in conjunction with a past perfect tense to indicate an event that is barely accomplished when another event happens.

- (b) I arrived than: The word "than" should be "when" to correctly complete the correlative conjunction "scarcely... when."

- (c) The train left: This part is grammatically correct.

- (d) No error: There is an error concerning the conjunction in part (b), so this option is incorrect.