のも尤(もっと)もだMay well, Have or has good reason for, No wonder, … Is only natural

のももっともだ is a combination of の, も, the な-Adjective もっとも, meaning 'reasonable', or 'plausible', and the auxiliary verb だ. In many cases, the interpretation will be 'it may well be (A)', 'it's only natural that (A)', or 'there's no wonder that (A)'. However, 尤(もっと)も itself is simply an adjective that affirms that the speaker understands the thought process behind (A), and that it is logical to them, regardless of whether or not they actually agree with it themselves. Due to this, 'it may well be (A)' in English is actually a very close translation of the feeling behind the expression.

のももっともだ will appear with verbs, い-Adjectives, な-Adjectives, and nouns. In the case of nouns, the の will be dropped, as the noun itself will become the expression being marked as the focus.

Due to のももっともだ being used when the speaker is expressing that they understand the underlying reasons behind something, phrases used for explanation such as から or ので will often be seen in the same sentence.