Select the option which is the most appropriate one word substitution for the given group of words.

Careful in performing duties

Punctilious

The most appropriate one-word substitution for the given group of words "careful in performing duties" is punctilious.

• Obedient means following orders or instructions.
• Sincere means honest and genuine.
• Punctual means being on time.

The word punctilious is the most appropriate because it specifically refers to being careful and exact in following rules or conventions. The other words do not have the same connotation of attention to detail.