What is one way the two major parties restrict the ability of third$-$party candidates to compete?

Ballot access laws require third$-$party candidates to achieve certain vote thresholds or gather many signatures to appear on the ballot.

The filing fee is often very high, which is a deterrent to third$-$party candidates.

The major parties can block third$-$party candidates from buying advertisements.

The major parties restrict the fundraising ability of third$-$party candidates.