Which set of learner characteristics may be considered helpful in designing effective teaching-learning systems? Select the correct alternative from the codes given below: 
1) Prior experience of learners in respect of the subject. 
2) Interpersonal relationships of learner’s family friends. 
3) Ability of the learners in respect of the subject. 
4) Student’s language background. 
5) Interest of students in following the prescribed dress code. 
6) Motivational-orientation of the students.