In the following, which answer is correct?

a$.$

AES$-128$ is more secure than DES because AES$-128$ has larger block size.

b$.$

AES$-128$ is more secure than DES because AES$-128$ is not a Feistel cipher.

c$.$

AES$-128$ is more secure than DES because AES$-128$ uses much longer key and non$-$linear operations on the finite field GF$(28).$

d$.$

AES$-128$ is not as secure as $2$DES$/2$