cobegin
x:= x + 3 || x := x + x + 2
coend
This implies that the two statements x:=x+3 and x :=x+x+2 can execute sequentially as well as parallelly..
Now,
Sequential part :
$x:= x + 3 \ || \ x := x + x + 2$
$x =1$ ( initial value )
First run $x = x+3$ , value of $x$ becomes $4$
Now $x=4$, run $x = x + x + 2$ value of $x$ will be $4+4+2=10$
Finally x becomes 10.
Parallel part:
Initialized value of $x =1$
Both will take $x$ as $1$ initially and then run independently, so
$x= x+3 = 1+3 = 4$
$x=x+x+2= 1+1+2 = 4$
But final write will be done by the process $x=x+x+2$
It will give value $4$.
$x=x+x+2$ completed its execution before $x=x+3.$
Then, x= x+3 will read value of $x$ as $4$ and then $x=x+3$ i.e. $x= 4+3 = 7$
So, here we get $\left \{ 4,7 \right \}$
Final answer is combination of both sequential and parallel part:
which is $\mathbf{\{ 4,7,10 \}}$
Option (C) .