The impedance matrices of two, two-port network are given by [3 2; 2 3] and [15 5; 5 25]. The impedance matrix of the resulting two-port network when the two networks are connected in series is ____________

• A. [3 5; 2 25]
• B. [18 7; 7 28]
• C. [15 2; 5 3]
• D. Indeterminate