According to the question, the reference graph is the one of the function y = sin x.
We can see that one unit was added to x in the argument:

But also, 1 was subtracted from the whole function:

Adding 1 to the x inside the argument of the sine function will move the graph one unit to the left. Finally, subtracting 1 to the whole function will move the graph one unit down.
Then, the correct answer is the first option.