In which decade was mercury-vapor artificial lighting developed to allow indoor filming without natural sunlight?

Idid the quiz. the true answers to this question is  2.michelangelo used the hatching technique of drawing parallel line close together  1.leonardo used the sfumato technique of blending and blurring chalk so edges nearly dissapear3.van gogh used a variety of expressive strokes to create different surfaces and textures. to the above answer, i got it wrong. i have copy-pasted from the question, putting the answers here.i hope this .  ~rosy67read more on -

All of the above have been used in film noir.

Iwould say asking questions. even over the small things because then you can get an answer that should you to understand more.