Among the following characters, which one was not considered by Mendel in his experiments on pea?

Among the following characters, which one was not considered by Mendel in his experiments on pea?

Option 1 : Seed – Green or yellow
Option 2 : Trichomes – Glandular or non-glandular
Option 3 : Stem – Tall or dwarf
Option 4 : Pod – Inflated or constricted