Today's Hiragana is お, it stands for "o". It is pronounced "oh", like the “o” in “original.”
Below is a video showing all the vowels, she says and writes all five. She speaks a little Japanese and has a heavy accent, so if you have any questions on what she says in Japanese or don't understand what she said in English, let me know and I'll do my best to help. I had a bit of a hard time understanding her English at some parts, but I think she still gets the important points across.