How do the trapdoors, within asymmetric algorithms, correspond with encryption, decryption, signature generation, and signature verification process?

A.
The easy direction does not require the trapdoor and carries out encryption and digital signature verification.

B.
The hard direction does not require the trapdoor and carries out decryption and signature generation.

C.
The easy direction does not require the trapdoor and carries out decryption and digital signature verification.

D.
The hard direction does require the trapdoor and carries out decryption and signature verification.

Explanation:
When a one-way function is carried out in the easy direction, then
encryption and digital signature verification functionality is available. When the
one-way function is carried out in the hard direction, then decryption and signature
generation functionality is available. What this means is that only the public key
can carry out encryption and signature verification and only the private key can
carry out decryption and signature generation.