Which set of segment lenghts could be used to construct a triangle

the complete question in the attached figure

we know that
To construct a triangle, two segments added together have to be greater than the 3rd segment, 
so
case A) 
2, 12, 19 
2+12 < 19------> these segments can not be used to form a triangle

case B) 
4, 7, 13
4+7 < 13------> these segments can not be used to form a triangle

case C) 
4, 5, 12 
4+5 < 12------> these segments can not be used to form a triangle

case D) 
13, 2, 12
13+2 > 12
13+12> 2
2+12>13
so
these segments can be used to form a triangle

the answer is
the option D) 
13, 2, 12
these segments can be used to form a triangle