Answer:
Each vendor want to sell as many as possible.
Explanation:
As the marginal cost is $1.5 for each hot dog sold and It is not increasing. The maximum amount of hot dogs each vendor want to sell is infinite because the marginal cost of $1.50 is lower than the price of $2. They will always earn extra $0.5 when they sell one hot dog. So, the desire of infinite profit the every vendor want to sell as many as he could to maximize their profit. Normally vendor sell the product until marginal cost equals the revenue / price.