Please kindly correct my grammar...

1. which one is correct
a. Matt like fish.
b. Matt likes fish.

Matt likes fish

For help with verbs:

http://www.englishclub.com/grammar/verbs.htm

For help with this particular singular/plural choice:
http://www.englishclub.com/grammar/verb-tenses_present-simple.htm
(Notice the -s on the 3rd person singular form.)

B. is the correct answer because the subject must agree with the verb in terms of number ('singular' or 'plural'). In order to achieve this, the written form of the subject and verb will be in the opposite. So when the subject is written in the singular form, the verb will be written in the plural form; and when the subject is plural, the verb will be written in the singular form. This, I call the 'rule of polarity' - elements of opposite charges will attract. For instance:

1. Derrick loves to listen to rock music.
a. Rule of agreement
subject: Derrick (one person - singular
verb: loves (one action - singular)
b. Rule of polarity
subject: Derrick (written - singular form)
verb: loves (written - plural form)
2. Derrick and Jason love to listen to rock music.
a. rule of agreement
subject: Derrick and Jason (two persons - plural)
verb: love (two actions - plural)
b. rule of polarity
subject: Derrick and Jason (written - singular form + singular form = plural form)
verb: love (written - singular form)
Note:
That this rule can also apply to the auxiliary verbs: 'Be' - (is, are, am [past tense: was, were]), 'Have - (has, have) and 'Do' - (does, do)

Sure! The correct sentence is:

b. Matt likes fish.

To explain the correction, let's look at the subject and verb agreement in the sentence. In this case, "Matt" is the subject of the sentence, and the verb that follows should match the subject. In English, when using the third person singular (he, she, it), we add an "s" to the verb.

Therefore, the correct form of the verb "like" is "likes" when it is used with "Matt" as the subject. So the correct sentence should be "Matt likes fish."