There are four concurrent processes $W,x,Y$ and $Z$ sequence. All have a shared variable $\text{'}c\text{'}.W$ and $x$ work as follow reads $c$ from memory, increment by one, store $c$ in memory. $Y$ and $Z$ work as follow reads $c$ 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 $s=1,$ what is the maximum value of $c$ after all four processes complete execution?

Select one:

a$.1$

b$.-1$

c$.2$

d$.-2$