Aerugo, also known as verdigris...

I think (A)
It is PRODUCED and not that IT PRODUCES anything so that eliminates B, C , D
between A and E i think WHICH is not required and A clearly communicates the intent of the sentence. Also A is concise

I vote for "E"

visible on many copper items, and is produced
at first glance seems correct, leave it for 2nd test
that is visible on many copper items, and which produces
changes meaning. It does not produce, it is produced
visible on many copper items, and produces
changes meaning. It does not produce, it is produced
that is visible on many copper items, and that produces
changes meaning. It does not produce, it is produced
which is visible on many copper items, and which is produced
Also ok

ok, now we are between A and E. Let's look at the structure.

A: Aerugo is a green bloom, (which ...) and is produced (...)

Here "is" and "is produced" are two verbs that relate to Aerugo. They are not parallel, since the first is active and the second is passive.

E: Aerugo is a green bloom , (which ...), and (which...)
Here both "which" clauses relate to the same subject ("green bloom") and are parallel.

So, E is better than A.

I will go with "A"

In E the construction " comma + and + which" is awkward.
waiting for an expert comment

himu wrote: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.

visible on many copper items, and is produced
that is visible on many copper items, and which produces
visible on many copper items, and produces
that is visible on many copper items, and that produces
which is visible on many copper items, and which is produced

In B, C and D, produces requires a direct object.
Since B, C and D do not indicate what the bloom produces, eliminate B, C and D.
The intended meaning is that AERUGO IS PRODUCED by the exposure of the metal.

In E, the second which refers to the green "bloom", implying that the BLOOM is produced by the exposure of the metal.
The intended meaning of the original sentence is that the subject of the sentence -- AERUGO -- is produced by the exposure of the metal.
Since E changes the intended meaning, eliminate E.

The correct answer is A.

E: the green "bloom" which is visible on many copper items
Generally, which serves to introduce a NON-ESSENTIAL modifier.
A non-essential modifier can be removed without changing the core meaning of the sentence.
But the modifier here -- visible on many copper items -- is ESSENTIAL, serving to define the green "bloom":
The green "bloom" VISIBLE ON MANY COPPER ITEMS.
Since which cannot serve to introduce an essential modifier. eliminate E.

Also, a which-modifier should generally be preceded by a COMMA.
The comma serves to indicate that the which-modifier is NON-ESSENTIAL.
Since no comma precedes the first which in E, eliminate E.