The correct answer is D. Popular sovereignty
Explanation:
Popular sovereignty is a political doctrine in which government and other political and administrative decisions derive from citizens. This usually implies citizens elect representatives and have a great influence on politics.
This principle is the one people lack in the passage because the author describes people who cannot manage public affairs "has kept us in a sort of permanent infancy with regard to public affairs". This means people are not deciding over government or internal administration and therefore there is no popular sovereignty.
17 people or patients have died due to a cochlear implant
I believe the correct answer is exercitui.
You need the perfect passive form here, which is formed when you combine the verb esse in the present tense (here, sunt because of third person plural), and the appropriate participle in the same person, which in this case is exercitui - third person plural.