What is the correct function to calculate the value of all orders marked COMPLETED?

a$.$

$=$SUMIF $($D$2$:D$9,$"completed",C$2$:C$9)$

b$.$

$=$SUMIF $($D$2$:D$9,$C$2$:C$9,$"COMPLETED"$)$

c$.$

$=$SUMIF $($C$2$:C$9,$D$2$:D$9,$"COMPLETED"$)$

d$.$

$=$SUMIF $($C$2$:C$9,$"COMPLETED",D$2$:D$9)$

e$.$

$=$SUMIF $($D$2$:D$9,$C$2$:C$9,$"completed"$)$