Problem 12-58 Resistor network

In the Figure, what is the
(a) current through the \(150 \Omega\) resistor?
(b) potential difference across the \(250 \Omega\) resistor?
(c) current through the \(350\Omega\) resistor?
(d) potential at \(\text{point A}\) (assuming zero potential at the negative terminal of the battery)

[Ans. (a) \(0.057 \;A\)   (b) \(14 \;V\)   (c) \(0.035\; A \)  (d) \(21 \;V\) ]

The object in questions like this is to determine the current provided by the battery. To do this we need to reduce the circuit to its simplest form, i.e. a single resistance \(R\) across the battery of voltage \(V.\)
 
Which resistors should be combined first?

(A)  \(150\Omega\) and \(350\Omega\)

(B)  \(550\Omega\) and \(250\Omega\)

(C)  \(350\Omega\) and \(550\Omega\)