There are four concurrent processes $W,x,Y$ and $Z.$ All have a shared variable $\text{'}c\text{'}.W$ and $x$ work follow reads $c$ from memory, increment by one, store $c$ in memory. $Y$ and $Z$ work as follow reads from memory, decrement by two, stores into memory. Each process of the four call wait on semaphore $s$ before reading, and calls signal after storing. If semaphore $s=2,$ what is the maximum value of $c$ after all four processes complete execution?

Select one:

a$.-2$

b$.2$

c$.1$

d$.-1$