In the following question, out of the four alternatives, select the alternative which will improve the bracketed part of the sentence. In case no improvement is needed, select "no improvement". They loaded their ships with spices and silks and returns with the summer monsoon.?

Option 1 : Returned

The correct answer is Option 1 ie Returned

Looking at the given sentence we find that:

• Then word loaded which is in the past tense or past participle. 
• So similar form of the verb should be used for return which is returned. 
• Return and Returning is present and present participle respectively and cannot be used here.

Hence we find that the only correct option that can be used here is Option 1 Returned which is the right answer. 

Thus the correct sentence will be: 'They loaded their ships with spices and silks and returned with the summer monsoon.'