Solution  

kills. at e or f is similar to at b.

Resistance 'a'

 

Resistance 'b'

 

Resistance 'c'

 

After , Black needs both x and y. only delays the problem for one more turn.

Resistance 'd'

 

White is caught in connect and die.

 

For other , works.

 

This might not be so obvious, but it works.