As Sarah and Maggie talk, Anna is worried that Sarah will leave. What does Sarah miss? Maggie? Anna?

From the text:

Maggie reached over and took Sarah's hand. "I miss the hills of Tennessee sometimes," she said.

"I miss the sea," said Sarah.

"I miss my brother William," said Sarah. "But he is married. The house is hers now. Not mine any longer. There are three old aunts who all squawk together like crows at dawn. I miss them, too.”

Anna:

"I would miss you, Nick," I whispered. "I would." I knelt down and scratched his ears. "I miss Mama."