GMAT Sentence Correction (SC) | Aerugo, also known as verdigris, is the green

Aerugo, also known as verdigris, is the green "bloom"visible on many copper items, and is produced, like iron rust, over the course of time by the exposure of the metal to the oxygen in the atmosphere.
a) visible on many copper items, and is produced - Correct
b) that is visible on many copper items, and which produces - produces is illogical
c) visible on many copper items, and produces - produces is illogical
d) that is visible on many copper items, and that - produces is
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