In a power or distribution transformer about 10 per cent end turns are heavily insulated__________?

In a power or distribution transformer about 10 per cent end turns are heavily insulated__________?

A. to withstand the high voltage drop due to line surge produced by the shunting capacitance of the end turns
B. to absorb the line surge voltage and save the winding of transformer from damage
C. to reflect the line surge and save the winding of a transformer from damage
D. none of the above