Black and White + 1

In CyberARTS, we have to make a photo black and white with a certain thing in colour. In order to do this we used masks. 

What I first did is make a gradient map adjustment layer to make it black and white. Then on the same layer, I made a mask to block out the adjustment so the colours can show.

I wanted to do something more with it, so I made a posterize adjustment layer and used the mask on the same layer to block everything except for the sunflower so the adjustment will only affect the sunflower. 

After that, I made a brightness and contrast adjustment layer to do some final touches. I like the result but I don't like the blown-out part on the top-right corner. But since it was cloudy when I took that photo, I can't help it.