After checking question
as @nitish said if multi buffer pipelined is allowed then only concept wise https://gateoverflow.in/3690/gate2004-it-47
this one is true, otherwise u need to wait for stall too.
Means if there is a stall means the previous stage is continuing
So, u cannot start next stage in next instruction
Though in GATE question this doesnot follow, as per my knowledge
So, just follow https://gateoverflow.in/3690/gate2004-it-47
I think GATE question follow multibuffer system , So, we havenot wait to still stall complete for an instruction, to start next stage.
Upto this I can tell,
I think ur doubt cleared
If more information I get , I will share
U can also share knowledge in this , if u get some information :)