Cognitive therapy would be the most suitable form of therapy for Nishant to overcome his problem of feeling miserable and unable to concentrate when he is not selected to represent the school for competitions. Cognitive therapy focuses on identifying and changing negative thought patterns and beliefs that contribute to emotional distress and maladaptive behaviors. In Nishant's case, his strong belief that everyone should love him and that he should always be selected for competitions is likely contributing to his feelings of misery and inability to concentrate when things do not go his way.

Identifying and challenging irrational beliefs
One of the key techniques used in cognitive therapy is identifying and challenging irrational beliefs. Nishant's belief that everyone should love him and that he should always be selected for competitions is unrealistic and likely contributing to his distress. A cognitive therapist would work with Nishant to help him recognize the irrationality of these beliefs and develop more realistic and adaptive ways of thinking.

Examining evidence and alternative explanations
Another important aspect of cognitive therapy is examining the evidence for and against our beliefs and considering alternative explanations. Nishant may have a tendency to overlook or discount evidence that contradicts his belief that everyone should love him and that he should always be selected for competitions. A cognitive therapist would help him examine the evidence more objectively and consider alternative explanations for why he may not always be selected, such as the presence of other talented individuals or subjective selection criteria.

Developing coping strategies
Cognitive therapy also involves developing coping strategies to deal with distressing thoughts and emotions. Nishant may benefit from learning techniques to challenge and reframe his negative thoughts, such as cognitive restructuring or thought stopping. Additionally, the therapist may help Nishant develop healthier ways of coping with disappointment and setbacks, such as problem-solving skills or relaxation techniques.

Promoting self-acceptance and self-worth
Finally, cognitive therapy aims to promote self-acceptance and self-worth. Nishant's strong need for external validation and approval may be undermining his sense of self-worth and contributing to his distress. A cognitive therapist would work with Nishant to help him develop a more balanced and self-compassionate view of himself, emphasizing that his worth as a person is not solely dependent on others' opinions or his achievements.

Overall, cognitive therapy would be the most suitable form of therapy for Nishant because it addresses the underlying cognitive distortions and beliefs that contribute to his distress and helps him develop more realistic and adaptive ways of thinking. By challenging irrational beliefs, examining evidence and alternative explanations, developing coping strategies, and promoting self-acceptance, cognitive therapy can help Nishant overcome his problem and improve his emotional well-being and ability to concentrate.