Option 1 : Sing the first verse and/or first chorus of Corrupted Flower.  (len's part bolded)

 [0:47-1:02] Lured in by the sweet scent, he had started his ascent 

 The butterfly flew down to where she had sat 

 She turned back to me with face so proud yet divine

 With a soft smile she met her eyes with mine

[1:17 - 1:50]  Intoxicated by a flower our own hearts consumed

On that dreaded day my love had sadly bloomed

Such a sweet yet thrilling scent,

From the poison god had lent,

the honey’s final calling

I could feel myself falling

Not even the thorns could stop the passion between us two 

And the flower thieves, whispered lies into each others ears 

Attempting to heal their own so sinful tears 

If you want to know more about me 

I want to know more about you 

Then tell me what you can do

I’ll tell you what I can do 

Yet once again the chain binds us closer to our sins

Option 2 : Sing any vocaloid song (in english) for more than 45 seconds.