Given the code of two processes that share the variable b whose initial value is $2,$

Process A:

$c=b-1$;

$b=2**c$

Process B:

$d=2**b$;

$b=d-1$;

how many distinct values $b$ can have at the end of execution

Select one:

a$.3$

b$.4$

c$.2$

d$.1$