Which of the following (words / phrase) is not positive as perceived by most customers?

"2- You’re welcome" phrase isn't positive and customers love to hear less.

Why You Shouldn't Say "You're Welcome"

Basically, the script is so deeply ingrained that you don’t even need to think about it. When you do a customer service, and client says “thank you,” the automatic response is “you’re welcome.” It’s a basic rule of politeness, and it signals that you accept the expression of gratitude or that you were happy to help. But according to one leading psychologist, this isn’t the best choice of words to deal with customers. After four decades of studying persuasion, Influence author Robert Cialdini has come to see “you’re welcome” as a missed opportunity. “There is a moment of power that we are all afforded as soon as someone has said ‘thank you,’”. To capitalize on this power, he recommends an unconventional reply: " I know you'd do the same for me."That doesn't relevant to customers service.

That view is opposite to what we do in our personal relations,where there are at least three potential advantages of this response. First, it conveys that we have the type of relationship where we can ask each other for favors and help each other without keeping score e.g. friends. Second, it communicates confidence that you’re the kind of person who’s willing to help others e.g. family. Third, it activates the norm of reciprocity, making sure that you feel obligated to pay the favor back in the future e.g. manager. Even So, Many customers service agents may wonder: How could I leave a “thank you” just hanging in the air without the proper acknowledgment?  That explanation fell apart, though, when I realized I could just combine politeness with  response: How can I help you? Wherein Customers appreciate the opportunity to explain exactly what they want and need from the service experience.

Ithink answer no. 4 is not positive

Thanks for your invitation.

I feel this is customer service self assessment question. Every answer have different rating, which help to judge our customer handling skill. 

For this single question, only negative answer is 'You're  Welcome".

I’ll do my best==================Answer

I think the answer choose is 3- I’ll do my best

I go for option 3. "I'll do my best". Thanks. 

I think the correct answer is : 4. What I can do is .....

3- I’ll do my best

4- What I can do is...

3- I’ll do my best..........................................

I agree with experts answers, thanks for the invitation. 

As for as my experience the customer really mind when u say what i can do this phrase has the feeling that u can do only a certain amount of things.