Given the lines:
L₁: r = 3i - 2j + 4k + ∂(4i + 2j - 3k)
L₂: r = i + 3j + k + δ(8i + 4j - 6k)
L₃: r = 2i + 6j + 2k + β(i - 4j + 4k)
L₄: r = 4i + 12j + 4k - μ(i + 3j + k).
Which pair of lines are parallel?
L₂ and L₄.
L₁ and L₂.
L₁ and L₄.
L₂ and L₃.
