S–subject
pn–predicate noun
do–direct object of verb
op–object of preposition

the bill must be paid by whoever purchased the lumber.

Explanation:

The sentence "The bill must be paid by whoever purchased the lumber" is written in the Passive Voice, in which the subject receives the action of the verb.

Subject: The bill

Predicate nominative/noun: paid  (after linking verb)

Direct Object of Verb: the lumber  (verb purchased)

Object of Preposition: whoever  (preposition by)

  this had halp

where are the multiple choice answers?