$\text { Figure } 16<2$ -The Purpose of Block 4 in Figure 16-2 Is to 4

$\text { Figure } 16<2$


-The purpose of Block 4 in Figure 16-2 is to ________.

A) keep the dc output voltage constant as the load changes
B) adjust the output voltage to the correct ac value
C) make sure that the fuse will not blow
D) maintain a constant output current when the load current changes