Step 1: Calculate the area of one square with 3 inches side.
The area of a square is given by the formula \( \text{Area} = \text{side}^2 \).
For Quantity A:
\[
\text{Area of one square} = 3^2 = 9 \text{ square inches}.
\]
Thus, the area of 4 squares with a side of 3 inches is:
\[
\text{Total area of 4 squares} = 4 \times 9 = 36 \text{ square inches}.
\]
Step 2: Calculate the area of one square with 4 inches side.
For Quantity B:
\[
\text{Area of one square} = 4^2 = 16 \text{ square inches}.
\]
Thus, the area of 3 squares with a side of 4 inches is:
\[
\text{Total area of 3 squares} = 3 \times 16 = 48 \text{ square inches}.
\]
Step 3: Comparison.
We have:
- Quantity A = 36 square inches
- Quantity B = 48 square inches
Since \( 36<48 \), Quantity A is less than Quantity B.
Step 4: Conclusion.
Therefore, the correct answer is option (3): Quantity A is less than Quantity B.