Answer:
C.) It indicates how long Fernand has been waiting for Mercedes to agree to marry him
Step-by-step explanation:
Indeed, the phrase; "here is Easter come round again" has an implied meaning in the story indicating the length of time that Fernard has waited.
For example, Easter holiday is celebrated once a year, so it's been up to or even more than a year since Fernard has been waiting for Mercedes to agree to marry him.