Hey there!
I believe your answer should be: OPTION B. because
7x + 2y - 14z = 56
7(8) + 2(28) - 14(4) = 56
56 + 56 - 56 = 56
112 - 56 = 56
56 = 56
So, that’s why possibly Option B. could be your result
Good luck on your assignment & enjoy your day!
~Amphitrite1040:)