The correct option is
D a-spermatheca, b-testis, c-seminal vesicle, d-ovary, e-vas deferens, f-accessory gland
In earthworm, there are four pairs of spermathecae present on 6th-9th segments. There are two pairs of testes present in the 10th and 11th segments.
One pair of ovaries is present at the intersegmental septum of the 12th and 13th segment. Their vasa differentia run up to the 18th segment where they the prostatic duct.
Two pairs of accessory glands are present one pair in each in the 17th and 19th segments.
So the correct answer is 'a-spermatheca, b-testis, c-seminal vesicle, d-ovary, e-vas deferens, f-accessory gland'.