Which of the following words can be used as a relative pronoun?

A relative pronoun is used to connect a clause or phrase to a noun or pronoun. The clause modifies, or describes the noun. The most common relative pronouns are who, whom, whose, which.

but = যে না, যা না – অর্থ হলে তা Relative Pronoun হয়।
যেমন- There is no mother but loves her child.