Which of the following are true about public key encryption:

Question $4$ Select one or more:

a$.$

for Alice to decrypt a public key encrypted message sent to her from Bob, she must use her "private" key

b$.$

for Alice to decrypt a public key encrypted message sent to her from Bob, she must use her "public" key

c$.$

for Alice to decrypt a public key encrypted message sent to her from Bob, she must use Bob's "public" key

d$.$

for Alice to decrypt a public key encrypted message sent to her from Bob, she must use Bob's "private" key