3.Charles Darwin observed that seed

3.Charles Darwin observed that seedlings grow towards light. He called this response ‘phototropism.’ In an experiment two light sources are used to illuminate each seedling. Each source is indicated by a yellow circle in the diagrams below. The larger yellow circle represents a light source with twice the illumination than the light source represented by the smaller yellow circle.
Which of the above responses would be
observed?
Sumber : International Junior Science
Olympiad (IJSO) 2013
(A) Only (iv)
(B) Only (ii)
(C) (i) and (iii)
(D) (i) and (iv)

Hasil (Bahasa Indonesia) 1:

3. Charles Darwin mengamati bahwa bibit tumbuh ke arah cahaya. Ia disebut respon ini 'phototropism.' Dalam percobaan dua sumber cahaya digunakan untuk menerangi masing-masing bibit. Masing-masing sumber ditandai oleh sebuah lingkaran kuning di diagram di bawah ini. Lingkaran kuning besar mewakili sumber cahaya dengan dua kali penerangan daripada sumber cahaya yang diwakili oleh lingkaran kuning kecil.Yang di atas tanggapan akan diamati?Sumber: Sains Junior Internasional Olympiad (IJSO) tahun 2013(A) hanya (iv)(B) hanya (ii)(C) (i) dan (iii)(D) (i) dan (iv)