Answer
(b) diagram .
Work Step by Step
When equal volumes of BaCl₂ and AgNO₃ have the same concentrations 0.1M combined, react all of AgNO₃ (aq) with 0.05M of BaCl₂ (aq) and remain 0.05 M of barium chloride unreacted, as included from the stoichiometric of the reaction:
BaCl₂ (aq) + 2AgNO₃ (aq) → 2AgCl (s) + Ba(NO₃)₂ (aq)
So, the beaker contains Ba²⁺, Cl⁻, NO₃⁻ ions and AgCl (s). This is best described in diagram (b).