The correct answer is: C. Vary equally depending on the core position
A LVDT (Linear Variable Differential Transformer) is a type of transformer that is used to measure linear displacement. It consists of a primary winding, two secondary windings, and a magnetic core. The primary winding is connected to an AC power source, and the secondary windings are connected to a voltmeter. When the core is in the center position, the two secondary voltages are equal in magnitude and opposite in phase. As the core moves away from the center position, the two secondary voltages increase in magnitude and remain opposite in phase. The difference between the two secondary voltages is proportional to the core position.
Option A is incorrect because the two secondary voltages are not independent of the core position. Option B is incorrect because the two secondary voltages vary equally depending on the core position. Option C is correct because the two secondary voltages vary equally depending on the core position. Option D is incorrect because the two secondary voltages are not always in phase quadrature.