Fixed it! New code below:

pagesToFormspec[pages_List] := 
 MapIndexed[<|
    "Title" -> <|"Label" -> #[["Title"]], "Required" -> False, 
      "Hidden" -> True|>, 
    "Description" -> <|"Label" -> #[["Description"]], 
      "Required" -> False, 
      "Hidden" -> True|>, {"page" <> 
       ToString[#2[[1]]], #[["Title"]]} -> #[["Choice"]], 
    "Page" -> <|"Label" -> ToString[#2[[1]]], "Required" -> False, 
      "Hidden" -> True|>|> &, pages]

questions = {<|"Title" -> "Question 1.1", 
   "Description" -> 
    "If the supply curve for orange juice is estimated to be Q = 40 + \
2p, then, at a price of p = 2, the price elasticity of supply is", 
   "Choice" -> <|
     "Interpreter" -> {"A" -> 1, "B" -> 2, "C" -> 3, "D" -> 4}, 
     "Control" -> RadioButtonBar|>|>, <|"Title" -> "Question 1.2", 
   "Description" -> "2+2 is", 
   "Choice" -> <|
     "Interpreter" -> {"A" -> 2, "B" -> 4, "C" -> 6, "D" -> 8}, 
     "Control" -> RadioButtonBar|>|>}

CloudDeploy[
 FormFunction[pagesToFormspec[questions], func, FormLayoutFunction ->
     (Grid[{{Annotation[
         Style[#["Title", "Label"], 
          "Section"], {"class" -> "form-title"}, 
                "HTMLAttrs"]}, {Annotation[
         Style[#["Description", "Label"], "Text"], 
                {"class" -> "form-description"}, "HTMLAttrs"]}, {#[
         "page" <> #["Page", "Label"][[1]]]}}, 
          Alignment -> Left] & )], "formtest"]

That's really great. Thank you.

Is it possible to add a "Back" button and also to display the choices in a column? All my attempts to do that ended in failure.