The best option is D studied.
This word denotes a measured, even-handed approach to the issue. So, it should be :Current immigration policy must be studied before new proposals can be made.
D, I just took apex right now
It is a warning that indicates a future event.
Repetition of similarly phonetic consonants is a skill for writing consonance. A poetic line with at least three words that shows technique of consonance is as below:
sit lit fit,
lit fit fit,
sit fit lit.
The techniques of consonance is usually used in a prosody. The similarly sounding consonants at the end of the poetic line is remarkably used in a creative poetry called as prosody.
