Search Engiries manage the heavy . . . . . . . . of keywords with URLs. A. machine B. network C. databases D. components

Option A, machine, is incorrect because search engines are not machines. They are software programs that run on computers.

Option B, network, is incorrect because search engines do not manage networks. They manage databases.

Option D, components, is incorrect because search engines are not made up of components. They are software programs that run on computers.