Which sentence correctly punctuates a direct address? 

1. Lisa can you help me?
2. Lisa, can you help me?
3. Lisa, can you help me
4. Lisa can you help me

Nouns of direct address need commas to separate them from the sentence (Chicago 6.38). This clarifies who is being spoken to. Missing commas (options a/d) cause confusion. Option c lacks a question mark for the interrogative.