(Solved): A transmission tower is held by three guy wires attached to a pin at \( \mathrm{A} \) and anchored ...

A transmission tower is held by three guy wires attached to a pin at \( \mathrm{A} \) and anchored by bolts at \( \mathrm{B}, \mathrm{C} \) and \( \mathrm{D} \). What is the component of the unit vector \( \mathrm{AB} \) in \( \mathrm{z} \) direction? Select one: a. \( L_{1} / \sqrt{ }\left(L_{3}^{2}+L_{1}^{2}+h^{2}\right) \) b. \( \left.-h / \sqrt{(} \mathrm{L}_{3}{ }^{2}+\mathrm{L}_{1}{ }^{2}+\mathrm{h}^{2}\right) \) d. \( h / \sqrt{\left(L_{3}^{2}+L_{1}^{2}+h^{2}\right)} \)