Need help please, it urgent.
Which event introduces the solution in this passage?

Tamica stood gasping at the window next to the gate, watching her plane taxi down the runway. It gained speed, its nose tilted skyward, and then it left the ground behind, tucking up its now-unneeded wheels as it soared toward the United States. This was not only Tamica's plane, it was also the night's last plane from London to the United States.
Tamica sat down right where she was to think. Her semester in the small English town of Sheffield was over, and she was supposed to be flying home right now. She'd moved out of the flat she'd shared with other students and all of her belongings were now airborne. She was faced with a long night in the airport or a night in the unfamiliar city of London.
"Mom, what am I going to do?" Tamica groaned on the phone.
"Tamica, I have a friend who lives near Heathrow Airport in London. I'll call her and try to have her come get you. Does that sound alright?"
"Yes, thank you!" Tamica exclaimed.
Outside the airport, Tamica sat down once again, still without luggage, but with a calmer mind. Home would have to wait until tomorrow.

Tamica spending a semester abroad in England
Tamica waiting outside for her ride
Tamica's phone call with her mom
Tamica missing her flight

As per the question, the event leading to a solution in the passage was 'Tamica's phone call with her mother.' Before the call, she was extremely tensed after missing her plane to the United States which was also the last plane for that night. She didn't know what to do as she had already left the place where she lived with other students and the city was not known to her. She was left clueless about how to spend the long night at the Heathrow airport but after the call, she gets to way to get out of this problem as one of her mom's friend live near the airport. Thus, this event brings a solution to her problem and hence, option C is the correct answer.