I do think the one with the bright orange/red tail looks a like she might be. The other 2 do not look pregnant, but there is a good chance that they are since they were being kept with males. Keep an eye on them and see if they start to get bigger. After being in contact with a male, female guppies can store sperm for up to 3 months. So, they may all have mated and time will tell if they are pregnant or not.
Have you tried the search function? It's the one that says, "search." It will search things for you.