Ans. is 'a' i.e., Panic attack * Sudden onset of breathlessness, anxiety, palpitation and feeling of impending doom suggest the diagnosis of panic attack (severe anxiety)* A panic attack has following characteristics: -A. Discrete episode of intense fearB. Abrupt onset (sudden onset)C. Reaches as maximum within few minutes and lasts for some minutes.D. At least four of the following symptoms : - 1) Palpitation 2) Sweating 3) Shortness of breath (Breathlessness) 4) Feeling of choking 5) Chest pain or discomfort (chest constriction) 6) Nausea or abdominal distress 7) Trembling or shaking 8) Dizziness, unsteady, fainting 9) Derealization or depersonalization 10) Fear of losing control 11) Fear of dying (impending doom) 12) Paresthesias 13) Chills or hot flushesE. At least one of the attack is followed by 1 month (or more) of one (or more) of the following ; - a) Persistent concern of future attacks, b) Worry about the consequences of attacks (Heart attack, Stroke) c) Significant change in behavior related to attack.