Step 1: Idea:
Use three-day totals first, then divide by 3. Each new total is the old total minus the value that leaves, plus the value that enters.
Step 2: First total.
$21+35+19=75$.
Step 3: Slide the window.
Drop 21 and add 27: $75-21+27=81$. Drop 35 and add 32: $81-35+32=78$. Drop 19 and add 22: $78-19+22=81$. Drop 27 and add 12: $81-27+12=66$.
Step 4: Divide each total by 3.
\[ \frac{75}{3}=25,\ \frac{81}{3}=27,\ \frac{78}{3}=26,\ \frac{81}{3}=27,\ \frac{66}{3}=22 \]
Step 5: Match.
The list 25, 27, 26, 27, 22 is option 3. The other options have wrong second or first values, so they are rejected.
Final Answer:
The moving averages are 25, 27, 26, 27, 22.
\[ \boxed{25,\ 27,\ 26,\ 27,\ 22} \]