Sentences given with blanks to be filled in with an appropriate word(s). Four…

Concept

In a passive-voice construction ("is/was + ___ + by X"), the blank must take a past participle. The irregular verb 'bear' splits into two past participles by a precise rule, not by meaning alone: 'born' is used ONLY in the passive voice for the sense of birth, and only when there is no following 'by + agent' phrase (e.g., 'The child was born in March'). The moment an explicit 'by' phrase names the agent - as in this sentence - or the construction is active/perfect (e.g., 'She has borne two children'), 'borne' is used instead, regardless of whether the sense is birth or the general sense of carrying, enduring, or sustaining.

Application

This sentence has exactly the trigger for 'borne': an explicit 'by consumers' phrase naming the agent after the passive verb. Even if the context were about birth, that trailing 'by' phrase alone would rule out 'born'. Here the sense is also non-birth (a price being carried/sustained), which independently confirms 'borne'.

Cross-check (why each other option fails)

• Bear - the base/present form of the verb; a passive construction after 'is' needs a past participle, not the base form, so it cannot fill the blank.

• Born - reserved for the passive-voice birth sense, and only usable when there is no following 'by + agent' phrase (e.g., 'the child was born in March'); this sentence has an explicit 'by consumers' phrase, which alone rules out this form here.

• Boar - a noun meaning a male pig; it is not any form of the verb 'bear' and cannot occupy a verb slot at all.

Result

'Borne' - the participle required whenever a 'by + agent' phrase follows the passive verb (or the construction is active/perfect), regardless of birth vs. non-birth sense; here it correctly completes: 'is borne, ultimately, by consumers.'