Step 1: Understanding the Concept
Apomixis is seed formation without normal fertilisation.
Step 2: Statement I
In adventive embryony, extra embryos arise from diploid nucellus or integument cells, so a seed has several embryos. This is polyembryony, so the statement is correct.
Step 3: Statement II
In non-recurrent apomixis the embryo develops from a haploid cell, so the plant is haploid and generally sterile, as in Nicotiana. This statement is also correct.
Final Answer:
Both statements are correct.
\[ \boxed{\text{(A) }\text{Both statement I and statement II are correct}} \]