Meaning of Perilous is Full of danger or risk.Meaning of Precarious is Not securely held or in position; dangerously likely to fall or collapse i.e. at a risk or danger.Meaning of Hazardous is Risky; dangerous.Meaning of Copious is Abundant in supply or quantity.As we can clearly see option A, B and C mean the same and thus, option D is the odd man out.Hence, option D is the correct answer.