Factor the following expression. \( z^{2}-1.6 z+0.64 \) Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. \( z^{2}-1.6 z+0.64=\square \) (Simplify your answer. Use integers or decimals for any numbers in your expression.) B. The given polynomial is not factorable.

To factor the expression \( z^{2}-1.6 z+0.64 \), we look for two numbers that multiply to \( 0.64 \) (the constant term) and add up to \( -1.6 \) (the coefficient of the linear term). The factors of \( 0.64 \) that meet this requirement are \( -0.8 \) and \( -0.8 \). Therefore, we can write the expression as: \[ z^{2} - 1.6z + 0.64 = (z - 0.8)(z - 0.8) \text{ or } (z - 0.8)^{2} \] So, the answer is: A. \( z^{2}-1.6 z+0.64=(z-0.8)^{2} \)