A can show the bears where the bulls are willing to make a stand. This can give confidence to the bulls and can make bears a bit less confident.
Possible small flag forming.
A is a taller candle with no shadows, or wicks on the top or the bottom. This one is red, but there is also a green candle. As a rule these candle may affect price on a very short basis and are a signal that continuation of the current trend may persist.
Can be a good idea to listen carefully to what the market is willing to give you, but you can't force the market to give you anything.