The code SQRT484 represents 22.
Examining the relationship:
222=484
484=22
The pattern codes a number n as SQRT(n2).
Applying this pattern to 29:
292=841
Therefore, 29 is coded as SQRT841.
Checking the options:
Option 1: CBRT1331 =31331=11
Option 2: SQRT721 =721≈26.85
Option 3: SQRT841 =841=29 ✓
Option 4: CBRT19683 =319683=27
Therefore, the answer is Option 3: SQRT841.