Adjective clause using "When"

Example	Explanation
I never forget the day. I have first date with you.              a.       I never forget the day when I have first date with you.              b.      I never forget the day on which I have first date with you.              c.       I never forget the day that I have first date with you.             d.      I never forget the day I have first date with you.	When is used in adjective clause to modify a noun of time (year, month, century, day, etc.) The use of a preposition in an adjective clause that modifies a noun in other adjective clauses: a preposition is used to preceding which as in (b). Otherwise, the preposition is omitted.