$1($a$)$ Explain the following

i$.$ Instruction Set Architecture $($ISA$)$

ii$.$ Program Counter

$(4$ Marks$)$

iii. Stack Pointer

$(4$ Marks$)$

$1($b$)$ Write on the mode following mode Addressing

i$.$ Immediate mode of addressing

Marks$)$

ii$.$ Direct Mode of Addressing

Marks$)$

iii. Indirect Mode

Marks$)$

iv$.$ Indexed Mode

$(4$