JEE Main 2021 Mathematics question

Consider the three planes : 3x + 15y + 21z = 9, : x – 3y – z = 5, and : 2x + 10y + 14z = 5 Then, which one of the following is true ?

• (A) and are parallel
• (B) and are parallelCorrect
• (C) and are parallel
• (D), and all are parallel