this is the best pet I _____.A ever haveB ever hadC hadD to have

this is the best pet I _____.A ever haveB ever hadC hadD to have
this is the best pet I _____.
A ever have
B ever had
C had
D to have

this is the best pet I _____.A ever haveB ever hadC hadD to have
答案是：I have ever had.（你漏了一个字）

选A。意思是：这是我曾拥有的最好的宠物。因为这只宠物现在仍然是最好的，所以不选B。