A$.$ put $$or $$ for the following sentences. $1-$ Address field in direct addressing mode contains the effective address of the operand$2-[].3-$ In base register addressing mode, the referenced register contains a main memory address $[].4-$ Thumb$-2$ is the only instruction set available on the Cortex$-$M microcontroller products $[].5-$ Thumb$-2$ instruction setIntroduces $32-$bit instructions $[].6-$ Greater capacity means smaller cost per bit$7-[].8-$ The address in direct mapping consist of tag, line number and word number $[].9-$ All semiconductor memory type are volatile$[].10-$ The unit of transfer from cache to processor is a block$[].$ B$.$ Answer the following questions. $1-$ What are the basic addressing modes? $2-$ Compare between Register Indirect and Displacement addressing modes by mentioning the advantage and disadvantage? $3-$ Name the our issues affected the design of instruction length? $4-$ Mention four key characteristics of computer memory system?