下列药物治疗子宫内膜异位症最有效的是

A．雄激素
B．雌激素
C．孕激素
D．避孕药
E．丹那唑

In the following essay, each blank has four choices. Choose the most suitable one from the four choices and write down in the answer sheet. There are two types of key technology: private key and public key. Private-key encryption methods are called (71) ciphers, information is encrypted with (72) both the sender and receiver hold privately. Public-key encryption methods are called (73) ciphers, (74) created for each user, encryption key and decryption key are (75)

A．same

B．different

C．difference

D．some