hi help it’s six grade maths HELPPPP?!

Answer:
B
Step-by-step explanation:
1. Work out the inequality
Add 3 to both sides to get n alone
15+3 = 18
18<n
2. Read the inequality
" n is greater than 18 "
3. Read each answer choice to see which matches up
B is the answer...B states "n is greater than 18"