Which marine habitats would have the least access to primary producers?
a. salt marshes and estuaries
b. coral reefs and lagoons
c. mangroves and intertidal zones
d. deep sea and sea floor

"Deep sea and sea floor" are the marine habitats among the following choices given in the question that would have the least access to primary producers. The correct option among all the options that are given in the question is the fourth option or option "d". I hope that this is the answer that has helped you.