VTMO 2026 - Grade 6 - Semifinal - SET 10 - Self-study Question 3

Let $N$ be the product of the odd numbers from 1 to 99, omitting those ending in 5 (5, 15, …): $N=1\times3\times7\times9\times11\times13\times17\times19\times\cdots\times91\times93\times97\times99$. What is the units digit of $N$?