Search all those stocks that traded at only one price today

Question | Sep 13, 2016 | hkumar 

We have a mongoDB collection - stocks - that contains all the stock symbols and their Open, High, Low and Close (OHLC) prices for today. These are some of the documents in that collection:

{ _id: 1, ticker: "AAPL", prices: { open: 106, high: 106.10, low: 105.20, close: 105.20 }, volume: 30300050 } 
{ _id: 2, ticker: "TSLA", prices: { open: 190, high: 210.12, low: 190.0, close: 205.20 }, volume: 10300070 }
{ _id: 3, ticker: "WMT", prices: { open: 80, high: 81.12, low: 78.4, close: 79.32 }, volume: 40300070 }
{ _id: 4, ticker: "DPZ", prices: { open: 34.12, high: 34.12, low: 34.12, close: 34.12 }, volume: 1030 }
.........

We want to find all those stocks that traded for at least $1 and traded at only one price. A stock traded at only one price if its High and Low prices are equal. Which one of followings is the correct query to find those stocks?

2015 nextptr