Frieda was helping her mom clean the house when they suddenly heard a strange sound from the attic. Frieda slowly walked up to the attic and was shocked by what she saw. "What happened?" her mother asked anxiously. "Mom, errr, your expensive vase has broken," Frieda said, biting her lip.
If someone wanted to shorten sentence 1 from the passage, which of the following uses correct punctuation?

A.
Frieda . . . when they suddenly heard a strange sound from the attic. .
B.
Frieda was helping her mom . . . when they heard a strange sound from the attic.
C.
Frieda was helping . . . heard a strange sound from the attic.
D.
Frieda was helping her mom clean the house . . . strange sound from the attic.