Answer:
option D.
Step-by-step explanation:
1) cosx=cotx;
[tex]cosx(\frac{1}{sinx} -1)=0;[/tex]
[tex]\left[\begin{array}{ccc}cosx=0\\sinx=1\end{array} \ = > \ \left[\begin{array}{ccc}x=\frac{\pi }{2} +\pi k\\x=\frac{\pi }{2} +2\pi n\end{array}[/tex]
where n,k∈Z;
2) if x∈[0;2π], then x=π/2; 3π/2.
Note, the greek letter 'Θ' is replaced with 'x'.
