Chem Doubts

H₂O is a polar protic solvent, and DMSO(dimethyl sulfoxide) is a weakly polar aprotic solvent. Polar protic solvents support S_N1 and tertiary substrates provide that.
In polar aprotic solvents, complete solvation does not take place. The cation is solvated but the anion remains free. It would support S_N2 but tertiary substrate will not give S_N2. It would rather give 90% elimination and 10% substitution. So c) is a possible answer for first where substitution is in poor yield in DMSO.

What's EAA?

Triple bonds are shorter than double bonds...so CO will have shorter bond length than CO₂.
Acetophenone, having COCH₃ group, does give yellow ppt in iodoform test.
Any acid evolves carbon dioxide on treatment with sodium bicarbonate.
So b), d) options for that.

1: b
reason: as it is a tertiary halide hence the carbocation formed will be higly stable moreover there is steric hinderance for SN2 to take place.
However ideally the reaction is with NaOH which is a strong base hence alpha beta elimination would be more probable than SN2