After signing an exclusive license contract with the patentee, Company A permits its subsidiary B to exploit the patented technology.
Company B and Company A have obtained the compulsory license right to license others to exploit the patented technology.
C company a sells products that it doesn't know infringe others' patents, and can prove that the products come from legal sources.
D company a manufactures its patented drugs without the consent of the patentee in order to provide the necessary information for administrative examination and approval.
Correct answer: D.