Question $8)$ The prospective short$-$circuit current between line and neutral is measured at $850$ A$.$ The maximum balanced prospective short$-$circuit current level between lines on a three phase system, as a rule of thumb, can be assumed to be approximately... a$)17$ kA b$)8\mathrm{.}5$ kA c$)0\mathrm{.}85$ KA d$)1\mathrm{.}7$ kA