To solve this problem, we need to identify the haploid, diploid, and triploid structures in a fertilized embryo sac of angiosperms. Let's analyze each structure:$\newline \bullet$Haploid structures:$\newline$ - In the embryo sac, the synergids and antipodals are haploid.$\newline$ - Synergids are located near the egg apparatus and play a role in guiding the pollen tube.$\newline \bullet$Diploid structures:$\newline$ - The zygote is formed by the fusion of the male gamete with the egg cell, making it diploid.$\newline \bullet$Triploid structures:$\newline$ - The primary endosperm nucleus is formed by the fusion of a male gamete with the two polar nuclei, resulting in a triploid structure.$\newline$Now, let's match these structures with the options:$\newline \bullet$Option 1: Synergids (haploid), Primary endosperm nucleus (triploid), and zygote (diploid) - Incorrect order.$\newline \bullet$Option 2: Antipodals (haploid), synergids (haploid), and primary endosperm nucleus (triploid) - Incorrect order and structures.$\newline \bullet$Option 3: Synergids (haploid), Zygote (diploid), and Primary endosperm nucleus (triploid) - Correct order.$\newline \bullet$Option 4: Synergids (haploid), antipodals (haploid), and Polar nuclei (haploid) - Incorrect structures.$\newline$Therefore, the correct answer is Option 3: Synergids, Zygote, and Primary endosperm nucleus.