Option B: 4
The distance of a point from the x-axis is the absolute value of its y-coordinate. For A(−3, −4), the y-coordinate is −4, so the distance = |−4| = 4 units.
Source: Chapter 7, Section 7.1
The key definition from Section 7.1: "The distance of a point from the x-axis is called its y-coordinate, or ordinate." Here, distance is always non-negative, so take the absolute value. The x-coordinate (−3) gives distance from the y-axis — a common trap in this question. Do not confuse the two.