Answer:
The correct answer is the Lord.
Step-by-step explanation:
Psalm 23 was written by David and it clearly praises the Lord.
The first line of the psalm is "The Lord is my shepherd, I lack nothing." After this, the speaker refers to the subject "He" in clear reference to the Lord. Even though the Lord is pictured as a shepherd, it shouldn't be understood literally but as a metaphor, which is a rhetorical device that compares two things or people in an implicit way. Trough this, the speaker gives the Lord all the good characteristics of a shepherd and that is why A is the correct answer.