As per the given above word , we get
Grave means seriously important,
inconsequential is something of no importance at all,
Solemn means serious and calm and can be anonymously used with Grave, Senile is to grow old and weaker.

Correct Option: B

As per the given above word , we get
Grave means seriously important,
inconsequential is something of no importance at all,
Solemn means serious and calm and can be anonymously used with Grave, Senile is to grow old and weaker.
From above it is clear that Inconsequential is opposite word of Grave .

As we can say that ,
Sedentary means something inactive or sleeping. Indolent means rude.

Correct Option: D

As we can say that ,
Sedentary means something inactive or sleeping. Indolent means rude.
Hence , Active is an opposite word of Sedentary .

As per the given above word , we can say that
Gradual refers to a slow and steady process, Rapid means quick and swift, dynamic means changing.

Correct Option: C

As per the given above word , we can say that
Gradual refers to a slow and steady process, Rapid means quick and swift, dynamic means changing.
Hence , Rapid is antonym word of Gradual.

The word Perspicuity (Noun) means: clarity. The word vagueness (Noun) means: no clarity in a person’s mind.

Correct Option: A

The word Perspicuity (Noun) means: clarity. The word vagueness (Noun) means: no clarity in a person’s mind.
Hence, the words perspicuity and Vagueness are antonymous.

The word Jettison (Verb) means : to throw something; abandon; to reject an idea.

Correct Option: A

The word Jettison (Verb) means : to throw something; abandon; to reject an idea.
Hence, the words jettison and accept are antonymous.