He is very careful and particular about everything he does.

A. Precise

B. Careless

C. Meticulous

D. Conscientious

Answer: Option C

Solution(By Examveda Team)

One word substitute is Meticulous.

Precise: marked by exactness and accuracy of expression or detail.
Careless: not giving sufficient attention or thought to avoiding harm or errors.
Meticulous: showing great attention to detail; very careful and precise.
Conscientious: wishing to do one's work or duty well and thoroughly.