Thinking the differences between agent functions and agent programs, select correct statements from following ones.

A、Therebemorethanoneagentprogramthatimplementsagivenagentfunction.;
B、Thereareagentfunctionsthatcannotbeimplementedbyanyagentprogram.;
C、Givenafixedmachinearchitecture,eachagentprogramimplementexactlyoneagentfunction.;
D、Keepingtheagentprogramfixedbutspeedingupthemachine,whiletheenvironmentisstaticandtheagentpaysnoattentiontothespeed,theagentfunctionshouldbechanged