option (D) 28 √6 is the answer
Explanation :
p =3√6 + 2√24 + 7√54
3√6 + 2√2×2×6+ 7√3×3×6
3√6 +2 ×2√6 + 7 ×3√6
3√6 +4√6 + 21√6
28√6
