To change an active sentence into the passive voice, the object of the active sentence becomes the subject of the passive sentence. The verb must be changed to a form of the verb "to be" followed by the past participle of the main verb. The tense of the original verb determines the form of "to be" that is used. 

To change the given sentence into the passive voice, "ten books" becomes the subject. Since "ten books" is plural and the tense is simple present, the correct form of the verb "to be" is "are." The past participle of "contain" is "contained." The location "in my school bag" remains unchanged, as the bag is not performing the action but is the place where the books are kept. The correct passive construction is: "Ten books are contained in my school bag."

Option B: This option is incorrect because the preposition "by" implies that the subject (in this case, "my school bag") is actively performing an action on the object ("ten books"). However, a school bag does not perform the action of containing in an active sense; it is simply the location or vessel. Therefore, "by my school bag" is not correct here.

Option C: This sentence is incorrect because "with" implies accompaniment or association rather than containment. Saying that books are "contained with" a bag suggests that both the books and the bag are contained together within something else, which changes the intended meaning .

Option D: This is grammatically incorrect. The preposition "to" does not convey the idea of location or inclusion. "Contained to" is not a standard or meaningful expression in English;.