Certificates are （71） documents attesting to the （72） of a public key to an individual or other entity. They allow verification of the claim that a given public key does in fact belong to a given individual. Certificates help prevent someone from using a phony key to （73） someone else. In their simplest form, Certificates contain a public key and a name. As commonly used, a Certificate also contains an （74） date, the name of the CA that issued the Certificate, a serial number, and perhaps other information. Most importantly, it contains the digital （75） of the certificate issuer. The most widely accepted format for certificates is X.509, thus, Certificates can be read or written by any application complying with X.509.

72（）

A．connecting

B．binding

C．composing

D．conducting

某企业将房屋租赁给A公司，未到期因故收回，应付A公司违约金20万元，请问，A公司应该给该企业开票吗？应在税务机关代开何种发票？