Increase Contribution to Pension or Invest in ETFs

Hi All

I am looking to invest a small amount per month ( say 100 euros per month). I am also putting 5% into a contributory pension from work. My question is

Which option is better
a) should I put 100 euro per month in S&P 500 ETF ( long term, I am thinking 20 years)
b) Increase my contribution to the pension (Say 100 euros before tax which will cost me 60 euros now)
c) any other option that I am not aware of

thanks
ramal

Option A isn’t even worth thinking about

Option B probably makes most sense

Option C would be to overpay your mortgage

Some argue for C; my own view is only do C if you have maxed out B. But it depends on your own personal circumstances too.

Will you be retired in 20 years?

Do you have children you want to pay for college education

Answers would inform if you want to save outside your pension