To determine the standard form of the complex number [tex]\( (24 - 10i) - (43 + 18i) \)[/tex], we need to perform the subtraction individually for both the real and imaginary parts.
1. Subtract the real parts:
[tex]\[
24 - 43 = -19
\][/tex]
2. Subtract the imaginary parts:
[tex]\[
-10i - 18i = -28i
\][/tex]
Combining these results, the standard form of the complex number is:
[tex]\[
-19 - 28i
\][/tex]
Thus, the correct answer is:
[tex]\[
\boxed{-19 - 28i}
\][/tex]
So, the correct option is:
[tex]\[
\mathbf{A. \, -19 - 28i}
\][/tex]