Select the product $(2+i)(-3-i)$ in the standard form $a+b i$
a.) $-5-5 i$
b.) $5-5 i$
c.) $6+i^{2}$
d.) $-6-i^{2}$

Step 1 ：The question is asking for the product of two complex numbers. The standard form of a complex number is \(a+bi\), where \(a\) is the real part and \(b\) is the imaginary part.

Step 2 ：To find the product of two complex numbers, we can use the distributive property to multiply each part of the first complex number by each part of the second complex number.

Step 3 ：Let's denote the first complex number as \(z1 = (2+1i)\) and the second complex number as \(z2 = (-3-1i)\).

Step 4 ：By multiplying these two complex numbers, we get the product as \(-5.0 - 5.0i\).

Step 5 ：The product of the two complex numbers is \(-5 - 5i\). This matches option a.) in the original question.

Step 6 ：Final Answer: \(\boxed{-5-5 i}\)