Determine which sentence has achieved a casual, yet professional tone.

a. The affected party cannot process the order indicated below until sizes are indicated.

b. We will send your order as soon as we have confirmed the sizes you need

b. We will send your order as soon as we have confirmed the sizes you need

Explanation:

The second sentence b) is more casual than the first sentence a) simply because the words used are part of everyday english language.

Despite that, the sentence in ordered in a manner that is both polite, and clear, which gives it a professional tone while at the same time being easy to understand, meaning that the sentence can easily achieve the goal of providing effective communication to the customer.