Factor completely. \( 25+10 b+b^{2} \) Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. \( 25+10 b+b^{2}=\square \) (Factor completely.) B. The trinomial is not factorable.

First additional information: To factor the expression \( 25 + 10b + b^2 \), we can rearrange it in standard form to get \( b^2 + 10b + 25 \). This trinomial is a perfect square, as it can be expressed as \( (b + 5)^2 \). The middle term, \( 10b \), is twice the product of the square root of the first term (\( b \)) and the square root of the last term (\( 5 \)). Second additional information: So, we can conclude that \( 25 + 10b + b^2 = (b + 5)(b + 5) = (b + 5)^2 \). This neat little trick of recognizing perfect squares can save time and help avoid mistakes when trying to factor more complicated expressions later on.