Write the distance formula of coordinate geometry for points A(x¹, y¹) and B(x², y²), and write the equation of the straight line passing through these two points A and B.

a) Distance formula: √((x²-x¹)² + (y²-y¹)²), Equation: y-y¹ = (y²-y¹)/(x²-x¹) * (x-x¹)
b) Distance formula: (x²-x¹)² + (y²-y¹)², Equation: y = mx + c
c) Distance formula: x²-x¹ + y²-y¹, Equation: y = mx + c
d) Distance formula: √(x²-x¹ + y²-y¹), Equation: y = mx + c