The 1st, 3rd, and 4th options.
1. 4+9 Rational
2. pi * 5 Pi is irrational and multiplying it by 5 doesn't change that.
3. 3.454545... is a rational number. If you do the math, it's 3 5/11
4. sqrt(16) * sqrt(4) is a rational number. It's 4 + 2 = 6
5. sqrt(7) x sqrt(2) is irrational.