Answer:
Option B
Explanation:
Please see the attached image 
Given - 
Allele for small pollen is "sp"
Allele for normal pollen is "sp+"
and "sp+" is dominant over "sp"
Allele for zebra necrotic tissue is "zn"
Allele for normal necrotic tissue is "zn+"
and "zn+" is dominant over "zn"
Cross is carried out between 
sp+ sp zn+ zn x sp+ sp zn+ zn
The gametes of the parent cells are - 
sp+ zn+, sp+zn, spzn+, spzn
The cross would be as follows 
           
 sp+ zn+	sp+zn	spzn+	spzn
sp+ zn+	sp+ sp+ zn+ zn+sp+ sp+ zn+ znsp+ sp zn+ zn+ sp+ spzn+ zn  
sp+zn	sp+ sp+ zn+ znsp+ sp+ zn znsp+ sp zn+ zn	sp+ sp zn zn
spzn+	sp+ sp zn+ zn+sp+ sp zn+ znsp sp zn+ zn+	sp sp zn+ zn
spzn	sp+ sp zn+ zn	sp+ sp zn zn sp sp zn+ zn	sp sp zn zn
Hence, option B is correct