Two – Motoko Kusanagi
She has a weird system, where she ranks people by how they figured out that she is a cyborg.
Kogami figured it out during one of their many sparring sessions. According to him, she was going too easy on him and pulling her punches.
"C'mon Major, you are starting to hit like a girl."
For his honesty, he received a black eye.
On the other hand, Juunanagou figured it out, because according to him, there was no way a real, human woman could look that drop dead gorgeous. But he was a bit of a jokester and a tease, so she didn't take his words seriously. He was probably trying to sweet talk his way out of paying his parking tickets.
"C'mon Major! How about some professional courtesy? I am a park ranger. You work for the police. We are in the same team!"
She almost expected him to shout something along the lines of, 'We are both cyborgs!'
But he didn't and she thought there was some hope left in this universe.
Now the way L figured out her secret was kinda embarrassing. Apparently, her choice of clothing proved to be revealing in more ways than one.
"It's December and you are dressed in a bustier and a thong. Either you are an Amazon Princess or a cyborg."
Later, on Christmas Eve when he asked her out on a date and when he had a bit too much to drink and told her with a slurred tone of voice that she was so beautiful that even Princess Diana would want to kiss her, Motoko found herself blushing just a little and when the two of them found themselves under a mistletoe, the two of them shared a kiss.
Months later, after Hikigaya joined the team and one day when everyone including L and Motoko were sharing old stories about themselves, the two of them learnt something new.
"The Princess of Wales!?" Motoko balked.
"Of course." L said. "Who did you think?"
"Wonder Woman! Princess Diana of Themyscira."
"Huh." L remarked. And then added. "I still stand by my statement. Diana, Princess of Wales is much prettier."
Hikigaya later had to talk to Motoko and tell her not to take it personally. Yeah, Wonder Woman was definitely hotter, but what can you do. L's British. You know how they feel about the royal family.