Option 1 -> Proficient means skilled or competent, not necessarily the best or foremost.
Option 2 -> Initial means first in time or sequence, not first in importance or quality.
Option 3 -> Ordinary means common or average, which is the opposite of premier.
Option 4 -> Leading means foremost or most important, which matches the meaning of premier.
Hence, Option 4: Leading -> "Premier" means first-rate, most important, or foremost in rank/quality, which aligns perfectly with "leading" when describing an institution -> correct