Whose child is Cathy pregnant with?

The father of the child Casey is carrying in "I Am Du Lala" is unknown. In the finale, Casey finally revealed that his child had nothing to do with Wang Wei. Related plots:

Kathy contacted Lala through Chen Yi. She asked Lala to meet, and both of them were calm. She softly described her current situation to the other party. Lala said that she was very comfortable living alone. Cathy said that she was already a mother and her child was named Yangyang. The sunny Yang was a boy, and Yangyang’s Dad is not Wang Wei.

Lara learned from Cathy’s words that she was not with Wang Wei. She was a little puzzled and asked Cathy why she had not considered being with Wang Wei, but Cathy solemnly said Answering her that this was exactly why she came to her today, she told Lala that Wang Wei was still waiting for her. When Lala heard this, her heart could not help but ripples, and she was very moved.

Kathy is pregnant:

After talking, Wang Wei and Lala returned to their hotel rooms. Cathy followed Wang Wei into his room. She told Wang Wei in a serious manner that she was pregnant and it was detected with a pregnancy test, and the child was his that day. Wang Wei was at a loss for a moment and he hesitated. And asked Cathy anxiously, are you sure?

Although he knew it was cruel to ask, he had just mustered up the courage to win back Lala, and at this time he could not afford any accidents. After hearing Wang Wei's words, Kathy could only say that maybe she should go to the hospital for a check-up.