Two flat plates of identical thickness and width $(w)$ have circular holes of diameter $d_1$ and $d_2$ at their center, as shown below. The plates are subjected to far$-$field uniaxial tensile stresses ${}_1$ and ${}_2,$ respectively. $d_1=40mm,d_2=70mm$ and $w=100mm.$ Both the plates will approximately have the same maximum stress if

a$){}_1=1\mathrm{.}15{}_2$

b$){}_1=1\mathrm{.}65{}_2$

c$){}_1=1\mathrm{.}85{}_2$

$($d$)){}_1=0\mathrm{.}85{}_2$