Q$3$ Which crack grows first?

$1$ Point

The brittle material shown below is loaded vertically with a tensile force. Crack lengths and radii of curvature are shown in yellow. As the force increases, where will a crack initiate FIRST? Select the cyan letter corresponding to the first point of crack propagation.

A

B

C

D

E

$\backslash ($ F $\backslash )($where$\text{'}$s F$?)$

None of the above