A
Digital security infrastructure
B
Food security infrastructure
C
Health care and education infrastructure
D
Telecommunication and transportation infrastructure
Correct answer: (a) Digital security infrastructure
Explanation
- A
Digital security infrastructure
Digital security infrastructure. Certificates, CAs, public-key crypto — PKI.
- B
Food security infrastructure
Food security. Unrelated.
- C
Health care and education infrastructure
Health and education. Unrelated.
- D
Telecommunication and transportation infrastructure
Telecom and transport. Unrelated.
Summary. Official key is (a). Public Key Infrastructure is the digital-security stack: certificate authorities, public/private keys, signatures for e-sign, e-tender, e-mail.