The correct option is A True
In triangle ABC,
AB=AC thus, ∠ABC=∠ACB (I) (Opposite angles of equal sides of triangle are equal)
Now, in △s DBC and ECB,
BC=BC (Common)
∠DBC=∠ECB=90 (Given)
∠EBC=∠DCB (From I)
Hence, △DBC≅△ECB (ASA Congruency)
or DC=BE (equal sides of triangle of opposite angle are equal)
Also, Given AB=AC
DC−AC=BE−AB
AD=AE