Which of the following expressions is equivalent to -5.4 - (2.1 + 1.8)?

A. -5.4 - (2.1 - 1.8)
B. -5.4 - (-2.1 - 1.8)
C. -5.4 + (-2.1 + 1.8)
D. -5.4 + -(2.1 + 1.8)