history of increasing dyspnoea and exercise- related syncope - left ventricular hypertrophy with widespread T wave inversion.. Transthoracic echo

A 34-year-old man is seen in the cardiology clinic . He has been referred by his GP with a history of increasing dyspnoea and exercise- related syncope. His father died suddenly when at the age of 42-years-old. An ECG attached to the admission letter shows left ventricular hypertrophy with widespread T wave inversion. Given the likely diagnosis, what is the most appropriate next investigation?
A. Cardiac angiogram
B. Transthoracic echo***
C. Transoesophageal echo
D. Exercise ECG
E. 24-hour ECG