Answer:
C
Step-by-step explanation:
To start this problem off, we should know an important trig rule:
[tex]\sin^2(\theta)+\cos^2(\theta)=1[/tex]
From here, it is simple:
[tex](\sin^2(\theta)+\cos^2(\theta))(\sin(\theta)+\cos(\theta))=\\1(\sin(\theta)+\cos(\theta))=\\\sin(\theta)+\cos(\theta)[/tex]
C
I hope this helps! Let me know if you have any questions :)
