Kevin wants to pay his credit card bill using the public Wi-Fi at a coffee shop. He borrows his friend's laptop for this. How can he ensure that his transaction is safe? Kevin should use a __________ and should make the transaction using __________.
a) VPN, Incognito mode
b) Firewall, Private browsing
c) Antivirus software, Public network
d) Two-factor authentication, Secure website (HTTPS)