Final answer:
Heteronormativity is the belief that heterosexuality is the natural or normal sexual orientation and represents a form of systemic bias or discrimination against other sexual orientations in society. Therefore correct option is A
Step-by-step explanation:
The belief that heterosexuality is the default or the normal sexual orientation from which other sexualities deviate is called heteronormativity. Heteronormativity is an ideological system that considers heterosexuality as the norm or standard for sexual orientation. This concept is deeply entrenched in societal norms and the structure of many societies, often leading to the marginalization of other sexual orientations. It is rooted in heterosexism, which are attitudes, bias, and discrimination in favor of heterosexuality over other sexual orientations. Heterosexism can lead to various forms of systemic inequality and personal distress for individuals who do not conform to this perceived norm.