A benchtop dc power supply acts as an ideal $4 \: A$ current source as long as its terminal voltage is below $10 \: V$. Beyond this point, it begins to behave as an ideal $10 \: V$ voltage source for all load currents going down to $0 \: A$. When connected to an ideal rheostat, find the load resistance value at which maximum power is transferred, and the corresponding load voltage and current.
- $\text{Shor}t, \infty \: A, 10 \: V$
- $\text{Open}, 4 \: A, 0 \: V$
- $2.5 \Omega, 4 \: A, 10 \: V$
- $2.5 \Omega, 4 \: A , 5 \: V$