【正确答案】 A

【答案解析】To solve this problem, you need to know how to graph xy-coordinates. Because point k is in the upper left quadrant, it must be negative. Eliminate answer choices C, D, and E. You are given that RS = ST. Because the coordinates of S are (k, 4), RS must equal 4 units. Therefore, ST must equal 4 units, and point S must be 4 units to the left along the x-axis. The x-coordinate, k, must be -4.