1. Identify the hybridisation in each allotrope

   • In graphite, each carbon atom is $sp^2$ hybridised.
   • In diamond, each carbon atom is $sp^3$ hybridised.

2. Find percentage of $p$-character in each hybrid orbital

   For hybridisation:

   • $sp^2$ means mixing of 1 $s$ orbital and 2 $p$ orbitals.

     Total parts $= 1+2=3$

     So, percentage of $p$-character is $\frac{2}{3}\times 100 = 66.67\% \approx 67\%$

   • $sp^3$ means mixing of 1 $s$ orbital and 3 $p$ orbitals.

     Total parts $= 1+3=4$

     So, percentage of $p$-character is $\frac{3}{4}\times 100 = 75\%$

3. Match with graphite and diamond

   • Graphite $\rightarrow sp^2 \rightarrow 67\%$ $p$-character
   • Diamond $\rightarrow sp^3 \rightarrow 75\%$ $p$-character

4. Check options

   • A: $33$ and $25$ $\rightarrow$ incorrect
   • B: $33$ and $75$ $\rightarrow$ incorrect
   • C: $50$ and $75$ $\rightarrow$ incorrect
   • D: $67$ and $75$ $\rightarrow$ correct

Hence, the correct answer is D.