hard will replace hardly
old things die hard mean stake a long time to change or end it (used) in Present Tense.

Correct Option: C

hard will replace hardly
old things die hard mean stake a long time to change or end it (used) in Present Tense.

knocked at the door will replace knocked the door
knocked (Verb) agrees with at (Prep.)
Hence, When she knocked at the door is the right usage.

Correct Option: A

knocked at the door will replace knocked the door
knocked (Verb) agrees with at (Prep.)
Hence, When she knocked at the door is the right usage.

from the Roman God will replace of the Roman God as – from (Prep.) is used for showing the origin of somebody/something
Look at the examples given below :
I’m from Bangalore.
These quotations are from Shakespeare.

Correct Option: C

from the Roman God will replace of the Roman God as – from (Prep.) is used for showing the origin of somebody/something
Look at the examples given below :
I’m from Bangalore.
These quotations are from Shakespeare.

Use of the (Def. Art.) is superfluous.
the (Def. Art.) is used before Superlatives, Ordinal Numbers and with Adjectives, for referring to a whole group of people
Look at the examples given below :
This is the highest building in Rohini.
This is the last chapter to be read.
The French enjoy cheese.
Hence, famous Bhishm will replace the famous Bhishm

Correct Option: B

Use of the (Def. Art.) is superfluous.
the (Def. Art.) is used before Superlatives, Ordinal Numbers and with Adjectives, for referring to a whole group of people
Look at the examples given below :
This is the highest building in Rohini.
This is the last chapter to be read.
The French enjoy cheese.
Hence, famous Bhishm will replace the famous Bhishm

is will replace are because –
‘Gulliver’s Travels’ is the name of a book and it agrees with Singular Verb.
Look at the examples given below :

Correct Option: B

is will replace are because –
‘Gulliver’s Travels’ is the name of a book and it agrees with Singular Verb.
Look at the examples given below :