Help me decide who should i ask for LOR

[wgong]

This is my last year for undergraduate.

First of all I don't know what exactly is a good relationship with professor. There are two professors I want to ask for LOR, I took 3 classes with both of them, and I went to their office hour a lot. (I didn't know I would ask for LOR one day, I was simply asking questions about the class) I believe they both remember my name. This is basically my relationship between these two professors, I don't know if I can consider this as a good or bad relationship, so I don't really know how should I ask them for LOR

 

The third professor: I don't think he remember my name. I took two classes with him and they are both really hard, I can barely see him during the office hour because everyone wants to ask question. However, I did really good on one of his group project based class. My group were in the final round of his project competition.

 

Research professor: I am start doing research this semester. During research,  I am either doing experiment with myself in the lab or with a graduate student, I barely see professor. Although research experience is good for app, I just dont know how could I ask him for LOR if we barely met.

 

The last one is my former employer. I did a summer internship in a start up. My boss was a young guy, 25ish, who just start the company about 6 months at the time. I didn't really do anything during that month, cause my boss didn't really know what to do (He is a business major and I am studying computer science). Although he offed to write LOR for me if I needed help in the future, I really have no idea what he can write for me just based on my work during on month. 

[bsharpe269]

Are you applying for masters or PhD programs?

[Flux2]

I have a similar question.

Can I ask for a LOR from a PI who doesn't know me and I worked for his lab for around 3months?

[peachypie]

How did you work in their lab for 3 months and they don't know you?  The answer is yes, assuming you do not have better options.

[wgong]

Are you applying for masters or PhD programs?

I am applying for master 

[hj2012]

You want a LOR from the professor in your lab. But instead of asking him first, you might want to talk to the grad student who was directly supervising your work about the best way to go about this. Many times, grad students can assist their PI in writing a more detailed letter.

The other two professors that you know well from class sound like good options to fill out the rest of the letters.