WILL RATE BRAINLIST TO ANYONE WHO ANSWERS WITH A EXPLANATIOn

130.5 cm²

Step-by-step explanation:

1) total length = 60 cm

Divided in ratio 7 : 3,  it's like it was divided on 7+3=10 pieces, and then were taken 7 pieces and 3 pieces.

60: 10 = 6 cm

6*7 = 42 cm big piece

6*3= 18 cm small piece

2) It was made squares.

A square  has 4 equal sides, so

42 : 4 = 10.5 cm is a side of the large square,

18: 4 = 4.5 cm is a side of the small square

3) Area of the square = side²

Area of the large square = (10.5)² = 110.25 cm²

Area of the small square = (4.5)² = 20.25 cm²

4) Total area of both squares

110.25 + 20.25 = 130.5 cm²

B is the right answer on Plato