Final answer:
The product of a complex number and its conjugate is 25.
Step-by-step explanation:
The product of a complex number and its conjugate can be found by multiplying the real parts and the imaginary parts of the complex numbers separately and then adding them together.
For the complex number 4-3i, the conjugate is 4+3i.
The product of 4-3i and its conjugate is (4)(4) + (-3)(3i) + (4)(-3i) + (-3i)(3i) = 23.
Therefore, the correct answer is a) 25.