Wisconsin, Illinois, Florida, and Minnesota have begun to enforce

@Capricorn369:

Let's look at the first part of the sentence:
'Wisconsin, Illinois, Florida, and Minnesota have begun to enforce statewide bans'
This part can stand on its own and hence it's an independent clause.

The next part of the sentence in options D and E are:
'leaves, brush, and grass clippings cannot be accepted in landfills' and
'landfills cannot accept leaves, brush, and grass clippings'
Both these sentences are independent clauses as well and as such, can stand on their own.
The first part of the sentence does not require the second part to complete its meaning. Hence, the second part is non-essential and is therefore a non-restrictive clause.

Now, we know that we use 'that' only when the clause is restrictive. If the clause is non-restrictive, we use 'which' so that the clause acts as subordinate to the main clause.

Had the options D and E been of the form:
'prohibit landfills from accepting leaves, brush and grass clippings.'
they would have been correct because the latter part would have then acted as a restrictive clause required to complete the meaning of the main clause and could have been aptly joined to the main clause using 'that'.

Hope this is clear now!