Q1: (b) — Rotations about different axes do not commute - Q3: (b) — $\hat{J}_+$ raises $m$ by 1, keeping $j$ fixed - Q5: (c) — Dimension is $2j+1 = 2(3/2)+1 = 4$ - Q7: (c) — The sign is $(-1)^{2j}$, distinguishing integer from half-integer - Q9: (b) — Single-valuedness of wavefunctions forces intege