Constant effort to achieve something
A. Perseverance
B. Attempt
C. Enthusiasm
D. Vigour
Answer: Option A
Solution (By Examveda Team)
One word substitute is Perseverance.Perseverance: persistence in doing something despite difficulty or delay in achieving success.
Attempt: make an effort to achieve or complete (something difficult).
Enthusiasm: intense and eager enjoyment, interest, or approval.
Vigour: physical strength and good health.

constant effort to achieve something is perseverance not attempt
Right answer for this question is perseverance. Kindly correct it.