After creating a set of keys using the elliptic curve algorithm with ssh$-$keygen, where the private key is stored by default?

a$./$etc$/$id$\_$rsa

b$./$etc$/$id$\_$ecdsa

c$./.$ssh$/$id$\_$rsa

d$./.$ssh$/$id$\_$ecdsa.pub

e$.\frac{}{.}ss\frac{h}{?}$ id$\_$ecdsa