Razor blades are examples product.
a. captive
b. optional
c. by-product
d. a or b
e. none of the above.

Captive product

Explanation:Captive products are the products that are manufactured for the purpose of being used with other core product.These product are made for the increment of the revenue by the sellers.Generally it is seen that captive products are high priced than the core product .Thus razor is supposed to be used with shaving cream/foam cream , therefore it is a captive product.

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the answer is a

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