Alternation of generations means that plants produce: a. only haploid multicellular organism b. only diploid multicellular organisms c. only diploid multicellular organisms with single-celled haploid gametes d. both haploid and diploid multicellular organism

Alteration of generations means that the plant produces both haploid and diploid multicellular organism.

Explanation:

Alteration of generation is known as metagenesis,which can be seen in some plants and algae that have distinct haploid sexual and diploid asexual stages.

The multicellular haploid gametophyte contain 'n' chromosome which alternates with diploid sporophytes that are diploid containing 2n chromosomes.

Two gametes of same species fuse with together and produces diploid zygote that develops into diploid sporophytes.

This relationship that occur between sporophytes and gametophytes  varies within different plant groups.

i believe it would be c: tons.