Tact - How would you grade these sentences?

Social Situations Unit 5 - Being polite:

How polite are these sentences? - Quiz

Select the correct answer from the choices given.

Looking over someone's shoulder when they're on the computer, you say:

You're doing that all wrong!
1. Likely to cause offence.
2. Not likely to be welcomed.
3. Tactful.
Looking over someone's shoulder when they're on the computer, you say:

Let me show you how to do that.
1. Likely to cause offence.
2. Not likely to be welcomed.
3. Tactful.
Looking over someone's shoulder when they're on the computer, you say:

Maybe we could do that another way.
1. Likely to cause offence.
2. Not likely to be welcomed.
3. Tactful.
You are bargaining for an antique and the dealer has just said "It's €200" so you say:

It's not worth that much!
1. Likely to cause offence.
2. Not likely to be welcomed.
3. Tactful.
You are bargaining for an antique and the dealer has just said "It's €200" so you say:

I'l give you €150.
1. Likely to cause offence.
2. Not likely to be welcomed.
3. Tactful.
You are bargaining for an antique and the dealer has just said "It's €200" so you say:

I'm sure it's worth that, but it's more than I can offer.
1. Likely to cause offence.
2. Not likely to be welcomed.
3. Tactful.
You are bargaining for an antique and the dealer has just said "It's €200" so you say:

I'm sure it's worth that, but it's more than I can offer.
1. Likely to cause offence.
2. Not likely to be welcomed.
3. Tactful.